Sepharose CL-6B Chromatography Research Articles

Purification and properties of a maltotriose-producing α-amylase from Thermobifida fusca

A maltotriose-producing α-amylase from Thermobifida fusca NTU22 was purified 7.2-fold as measured by specific activity from crude culture filtrate by ammonium sulfate fractionation, Sepharose CL-6B and DEAE-Sepharose CL-6B column chromatography. The overall yield of the purified enzyme was 22%. The purified enzyme gave an apparent single protein band on SDS-polyacrylamide gel electrophoresis (SDS-PAGE). The molecular mass of purified enzyme as estimated by SDS-PAGE and by gel filtration on Sepharose CL-6B to be 64 and 60 kDa, respectively, indicated that the maltotriose-producing α-amylase from T. fusca NTU22 is a monomer. The optimum pH and temperature for the purified enzyme were 7.0 and 60 °C, respectively. About 70% of the original activity still remained after treatment at 60 °C for 3 h. The enzyme activity was completely inhibited by 1 mM Hg 2+. The K m value for soluble starch was 0.88 mg/ml. The purified enzyme exhibited a high level of activity with raw sago starch. Maltotriose was formed as the major enzymatic product from both soluble starch and raw sago starch.

Binding of trans -acting protein AngCP to the CCAAT-containing motifs in Aspergillus niger glaA promoter*

Abstract CCAAT-binding proteins AngCPl and AngCP2 of Aspergillus niger binding to DC (− 489 ∼ −414 bp) and PC (−390∼ −345 bp) of A. niger glaA gene were respectively purified by 20% ∼ 40% saturated ammonium sulfate, gel filtration. Heparin SepharoseCl-6B chromatography and DNA sequence-specific affinity chromatography. Gel filtration and SDS-PAGE revealed that both AngCPl and AngCP2 were of 120 kD. comprised of two subunits of 34 kD and 50 kD. Western blot showed that the 34 kD subunits of both AngCPl and AngCP2 cross-reacted specifically with the anti-AngHAPC antiserum. Further electrophoretic mobility shift assay identified that AngCPl and AngCP2 were the same protein, designated AngCP. Southwestern blot showed that the affinity of the 34 kD sub-unit to DC was stronger than that of the 50 kD subunit to PC. These results suggested that interaction between AngCP, DC and PC plays an important role in the regulation of transcription of Aspergillus niger glaA gene.

Characterization of Chondroitin/Dermatan Sulfate Proteoglycans Synthesized by Bovine Retinal Pericytes in Culture

Pericytes associate with the outside of endothelial cells in microvessels. Previous studies have shown that these cells synthesize glycosaminoglycans (GAGs) but the nature of the core proteins to which these GAGs are attached is unknown. In the present study, cultured bovine retinal pericytes were metabolically labeled with [(3)H]glucosamine, [(35)S]sodium sulfate or (35)S-labeled amino acids and the proteoglycans synthesized by these cells were purified by DEAE-Sephacel ion exchange and molecular sieve Sepharose CL-4B chromatography. Separated proteoglycans were digested with papain, heparitinase or chondroitin ABC lyase and the GAGs characterized by Sepharose CL-6B chromatography. Proteoglycans were also assessed by sodium dodecyl sulfate polyacrylamide gel electrophoresis before and after digestion with chondroitin ABC lyase. Pericytes predominantly synthesize and secrete chondroitin or dermatan sulfate proteoglycans (CS/DS PGs) rather than heparan sulfate proteoglycans (HSPGs). Two subclasses of CS/DS PGs are synthesized by pericytes; one is a high M(r) subclass with high charge density. This subclass eluted at the void volume of a Sepharose CL-4B molecular sieve column, was susceptible to chondroitin ABC lyase, and contained core proteins of ca. 550 and 450 kD which were recognized by antibody to versican. The other major subclass eluted at a K(av) ca. 0.45 on a Sepharose CL-4B molecular sieve column, was susceptible to chondroitin ABC lyase, and contained core proteins recognized by antibodies to either biglycan or decorin that separated as a broad band of ca. 50 kDa in SDS-PAGE. A small amount of HSPG was also synthesized by these cells and could be separated from the CS/DS PGs by DEAE-Sephacel chromatography using a linear gradient of 0.1-0.7 M NaCl. Release of GAG chains by protease digestion indicated that the length of GAG chains was approximately M(r) 45000 in biglycan and decorin, approximately M(r) 48000 in the small amount of HSPGs and approximately M(r) 66000 in versican. These proteoglycans resemble those synthesized by vascular smooth muscle cells but differ markedly from those synthesized by vascular endothelial cells.

Regulation of Glomerular Endothelial Cell Proteoglycans by Glucose

The presence of heparan sulfate proteoglycan (HSPG) in anionic sites in the lamina rara interna of glomerular basement membrane suggests that the proteoglycan may be deposited by the glomerular endothelial cells (GEndo). We have previously demonstrated that bovine GEndo in vitro synthesize perlecan, a species of glomerular basement membrane HSPG. In this study we examined whether high glucose medium regulates the GEndo metabolism of glycopeptides including perlecan. Metabolic labeling of glycoconjugates with 35S-SO4, sequential ion exchange and Sepharose CL-4B chromatography of labeled glycoconjugates, and northern analysis were performed. Incubation of GEndo for 8 to 14 weeks (but not for 1-2 weeks) in medium containing 30 mM glucose resulted in nearly 50% reduction in the synthesis of cell layer and medium 35SO4-labeled low anionic glycoproteins and proteoglycans, including that of basement membrane HSPG (Kav 0.42) compared to GEndo grown in 5 mM glucose medium; no changes in anionic charge density or hydrodynamic size of proteoglycans were noted. Northern analysis demonstrated that the mRNA abundance of perlecan was reduced by 47% in cells incubated with 30 mM glucose. Our data suggest that high glucose medium reduces the GEndo synthesis of perlecan by regulating its gene expression. Reduced synthesis of perlecan by GEndo may contribute to proteinuria seen in diabetic nephropathy.

Comparison of pyruvate kinase variants from breast tumor and normal breast

Background. Pyruvate kinase isozymes in human breast tumor tissue were compared in this study with normal human breast tissue. Two forms of pyruvate kinase present in normal and tumor human breast were purified by ammonium sulfate precipitation, dialysis, gel filtration, ion exchange, and affinity chromatography. Molecular weight of the native enzyme was determined. Methods. Presence of pyruvate kinase activity was examined in normal and tumor breast tissues. Pyruvate kinase was purified with Sephadex DEAE-50, Sepharyl S-200, and Blue Sepharose CL-6B chromatography. Spectrophotometric methods were used to determine activities of pyruvate kinase. Results. Molecular weights of fractions I and II as determined by gel filtration on Sepharyl S-200 were 135,000 Da, 260,000 Da in normal breast tissue, and 72,000 Da, 250,000 Da in tumor breast tissue, respectively. Fractions I and II of pyruvate kinase may be purified approximately 1,591-fold, 636.4-fold in normal breast tissue and 219-fold, 318-fold in tumor breast tissue, respectively. Pyruvate kinase activity in tumor tissue was found higher than in normal tissue. Only tumor fraction II showed tumor-specific sensitivity to L-cysteine. L-phenylalanine inhibited both fractions I and II of normal breast and fraction I of tumor breast, but not fraction II of pyruvate from tumor. ATP inhibited normal and tumor fraction I of pyruvate kinase. The influence of ATP on enzyme activity from normal and tumor fraction II depended upon its concentration. Conclusions. It was thought that isozymes of pyruvate kinase from human breast tissue might be M1 and M2 isozymes when compared with those of other tissue pyruvate kinase isoenzymes. Fraction II from breast tumor represented different sensitivity to L-cysteine, L-phenylalanine, and specific activity in comparison with fraction II from normal breast. Different kinetic behavior of fractions in the human breast tumors may support the concept of an isozyme shift.

Detection and characterization of the Gloeosporium gloeosporioides growth inhibitory compound iturin A from Bacillus subtilis strain KS03

The Bacillus subtilis strain KS03 was isolated, and identified as a biological control agent that inhibits the anthracnose disease fungus Gloeosporium gloeosporioides. The antifungal compound was purified from its culture broth through butanol extraction, diethylaminoethyl (DEAE) Sepharose CL-6B chromatography, and preparative thin layer chromatography. Tandem mass spectrometric analyses (MS/MS), with matrix-assisted laser desorption ionization (MALDI) time-of-fight/time-of-flight (TOF/TOF) mass spectrometry, showed that the antifungal compound was iturin A, a cyclic lipopeptide antibiotic. The major compound, with a molecular mass of 1042 Da, was identified as iturin A 2.

Glyceraldehyde-3-phosphate dehydrogenase from the newt Pleurodeles waltl. Protein purification and characterization of a GapC gene

The NAD +-dependent cytosolic glyceraldehyde-3-phosphate dehydrogenase (GAPDH, EC 1.2.1.12) has been purified to homogeneity from skeletal muscle of the newt Pleurodeles waltl (Amphibia, Urodela). The purification procedure including ammonium sulfate fractionation followed by Blue Sepharose CL-6B chromatography resulted in a 24-fold increase in specific activity and a final yield of approximately 46%. The native protein exhibited an apparent molecular weight of approximately 146 kDa with absolute specificity for NAD +. Only one GAPDH isoform (p I 7.57) was obtained by chromatofocusing. The enzyme is an homotetrameric protein composed of identical subunits with an apparent molecular weight of approximately 37 kDa. Monospecific polyclonal antibodies raised in rabbits against the purified newt GAPDH immunostained a single 37-kDa GAPDH band in extracts from different tissues blotted onto nitrocellulose. A 510-bp cDNA fragment that corresponds to an internal region of a GapC gene was obtained by RT-PCR amplification using degenerate primers. The deduced amino acid sequence has been used to establish the phylogenetic relationships of the Pleurodeles enzyme — the first GAPDH from an amphibian of the Caudata group studied so far — with other GAPDHs of major vertebrate phyla.

Purification and characterization of a novel chitinase from Burkholderia cepacia strain KH2 isolated from the bed log of Lentinus edodes, Shiitake mushroom.

One of the chitinases secreted in the culture filtrate of a gram-negative bacteria, Burkholderia cepacia strain KH2, which was isolated from the bed log of Lentinus edodes, Shiitake mushrooms, was purified by DEAE Sepharose CL-6B chromatography, followed by Sephacryl S-100 HR gel filtration. The purified enzyme was homogenous, determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), with an estimated molecular weight of 34,000 and an isoelectric point (pI) of 5.9. The enzyme was stable at pH values of 4.0-6.0, and at temperatures up to 50 degrees C; the optimum pH and temperature were 4.5 and 50 degrees C, respectively. The enzyme exhibited higher activities toward chitosan 7B, a 62% deacetylated chitosan, than toward the highly deacetylated chitosan substrates. The enzyme was observed to drastically hydrolyze partially deacetylated chitin substrates, with the subsequent formation of N-acetylchitooligosaccharides [(GlcNAc) (n), n=2-7]. Separation and quantification of the hydrolysis products of (GlcNAc) (n), n52-6, by HPLC showed the splitting into (GlcNAc)(n), n=3-6. Activity toward N-acetylchitobiose was not detected. Oligomers with a higher number of units than the starting substrate were also detected, which indicate transglycosylation activity.

Isolation and purification of BV?-2H from bee venom and analysis of its biological action

The medical use of bee venom for rheumatoid arthritis (RA) has a very long tradition. In this study, isolation and purification of polypeptides from bee venom were carried out on sephadex chromatography, heparin sepharose CL-6B chromatography and HPLC. Several fractions were extracted, and their effects on activation of splenocyte and THP-1 cell were studied. The inhibitory fraction was selected for further studies. Finally, BV I -2H that the HPLC elution profiles was a single peak was isolated by C8 column. ESIMS detection results showed that BV I -2H was a fraction of bee venom, and the molecular weight of the major component was 644.8. BV I -2H could inhibit ConA-induced splenocyte proliferation, IL-1 production and interfere with splenocyte cycle in mice. Moreover, BV I -2H could inhibit PMA-induced TNFα production in THP-1 cells, which was due to its inhibitory effects on TNFα mRNA expression and protein phosphorylation of IκBα. Our studies indicated that BV I -2H was one of the anti-inflammatory components of bee venom.

Characterization of mucin in gut lavage fluid obtained from inflammatory bowel disease

Gut lavage fluid, collected by the oral administration of an electrolyte lavage solution, was found to be an excellent and easily collectible source of abundant mucin. Furthermore, the biochemical features of mucin from patients with ulcerative colitis (UC) and Crohn's disease (CD) were investigated. The mucin was separated into four fractions by Sepharose CL-4B, Sepharose CL-2B, and DEAE Sephacel chromatography. Compared to healthy subjects, the total yields of mucin from ulcerative colitis patients were low due to a deficiency of neutral mucin, whereas those from Crohn's disease patients were high, mainly due to high-molecular-weight mucin. Fucose and sulfate content was low in ulcerative colitis, but only the former was low in Crohn's disease. The different biochemical features of mucin obtained from gut lavage fluid appear to reflect the mucosal pathological changes associated with inflammatory bowel disease.

Differential effects of cadmium on proteoglycan synthesis of arterial smooth muscle cells: increase in small dermatan sulfate proteoglycans, biglycan and decorin, in the extracellular matrix at low cell density

Proteoglycans (PGs), especially chondroitin/dermatan sulfate proteoglycans (CS/DSPGs), accumulate and their composition variously changes in atherosclerotic vascular walls. Since cadmium causes atherosclerosis in experimental animals, PGs synthesized by cultured vascular smooth muscle cells after exposure to cadmium were characterized in the present study. Sparse and dense cultures of the cells were metabolically labeled with [ 35S]sulfate for 24 h in the presence of cadmium chloride at noncytotoxic levels (0.2 μM or less). The incorporation of [ 35S]sulfate into glycosaminoglycans was determined by the cetylpyridinium chloride precipitation method. The labeled PGs were characterized by DEAE-Sephacel ion exchange chromatography and Sepharose CL-4B molecular sieve chromatography. The M r and the glycosaminoglycan composition of small CS/DSPGs were analyzed by SDS-polyacrylamide gel electrophoresis and Sepharose CL-6B chromatography, respectively, before and after digestion with chondroitin ABC lyase or papain. The core proteins were identified by Western blot analysis. These experiments indicate that cadmium differentially acts on the PG synthesis when vascular smooth muscle cell density is low. Specifically, cadmium increased the accumulation of small CS/DSPGs identified as biglycan and decorin in the cell layer of sparse cells. However, the hydrodynamic size and the length of chondroitin/dermatan sulfate chains in the PGs were unaffected by cadmium. On the other hand, cadmium decreased other cell layer-associated PGs that were separated from biglycan and decorin by DEAE-Sephacel chromatography in the sparse cells; as the result, whole glycosaminoglycans were decreased in both the cell layer and the conditioned medium. It is therefore concluded that cadmium may change the composition of PGs in atherosclerotic plaques through induction of biglycan and decorin synthesis and inhibition of other PG synthesis in vascular smooth muscle cells.

Antisense Inhibition of Decorin Expression in Myoblasts Decreases Cell Responsiveness to Transforming Growth Factor β and Accelerates Skeletal Muscle Differentiation

Decorin is a member of the family of the small leucine-rich proteoglycans. In addition to its function as an extracellular matrix organizer, it has the ability to activate the epidermal growth factor receptor, and it forms complexes with various isoforms of transforming growth factor beta (TGF-beta). Decorin is expressed during skeletal muscle differentiation and is up-regulated in dystrophic muscle. In this study we investigated the role of decorin in TGF-beta-dependent inhibition of myogenesis. To probe the function of decorin during myogenesis, C(2)C(12) myoblasts were stably transfected with a plasmid expressing antisense decorin mRNA. The resulting inhibition of decorin expression led to the expression of myogenin, a master transcription factor for muscle differentiation, under growth conditions and accelerated skeletal muscle differentiation as determined by the expression of creatine kinase. In contrast myogenin expression was inhibited by adenovirally induced decorin expression or by adding exogenous decorin. Reduced synthesis of decorin resulted in a 7-fold decreased sensitivity to TGF-beta-mediated inhibition of myogenin expression. In contrast, adenovirally induced decorin expression in wild type cells resulted in a 5-fold increased sensitivity to TGF-beta-mediated inhibition of myogenin expression. Transfection studies with the TGF-beta-dependent promoter of the plasminogen activator inhibitor-1 coupled with luciferase revealed that the transducing receptors for TGF-beta1 and TGF-beta2 were involved in the different responses of wild type and antisense decorin myoblasts. These results demonstrate that a reduction of decorin expression or of decorin availability results in a decreased responsiveness to TGF-beta. These findings strongly suggest a new role for decorin during skeletal muscle terminal differentiation by activating TGF-beta-dependent signaling pathways.

Purification and characterization of a chitinase from Trichoderma viride.

Usukizyme, a commercial enzyme preparation from Trichoderma viride, showed multiple chitin- degrading activities. One of these was purified to homogeneity by sequential DEAE Sepharose CL-6B, Q-Sepharose FF, and Sephacryl S-100 HR column chromatographies. The purified enzyme showed optimum activity at pH 3.5 and 50 degrees -55 degrees C and was stable in the pH range of 3.5-6.0 and up to 45 degrees C. It showed higher activity toward chitosan-7B, a 62% deacetylated chitosan, as opposed to highly deacetylated chitosan substrates. Products of degradation of a 1% (w/v) solution of partially deacetylated chitin (PC-100) were purified on CM-Sephadex C-25 and analyzed by HPLC, exo-glycosidase digestion, and nitrous acid deamination. The enzyme was unable to split the GlcN-GlcN linkages in the substrate. It produced mainly (GlcNAc)(2) and (GlcNAc)(3) along with mixed oligosaccharides. When subjected to nitrous acid degradation, some of the mixed oligosaccharides produced mainly 2-deoxyglucitol, implying the presence of GlcN at the reducing end of the oligosaccharides.

Proteoglycans synthesized by cultured bovine aortic smooth muscle cells after exposure to lead: lead selectively inhibits the synthesis of versican, a large chondroitin sulfate proteoglycan

To investigate the effects of lead on the formation of extracellular matrix in the vascular wall, we characterized proteoglycans synthesized by cultured vascular smooth muscle cells after exposure to the metal by biochemical techniques. Confluent cultures of bovine aortic smooth muscle cells were metabolically labeled with [ 35S]sulfate or [ 35S]methionine/cysteine in the presence of lead nitrate. The amount of glycosaminoglycans (GAGs) was evaluated by the incorporation of [ 35S]sulfate into GAGs by the cetylpyridinium chloride precipitation method. The labeled proteoglycans were characterized by DEAE-Sephacel ion exchange chromatography and Sepharose CL-2B molecular sieve chromatography. The GAG M r and composition were analyzed by Sepharose CL-6B chromatography, and the core protein M r was analyzed by SDS-polyacrylamide gel electrophoresis, before and after digestion with papain or chondroitin ABC lyase. Lead significantly decreased the [ 35S]sulfate incorporation into GAGs accumulated in the cell layer and the conditioned medium. [ 35S]Sulfate-labeled proteoglycans obtained from the cell layer and the conditioned medium were separated into three peaks on DEAE-Sephacel chromatography and only the peak with the highest charge density was decreased by lead. The highly charged peak was eluted near the void volume on Sepharose CL-2B molecular sieve chromatography and sensitive to chondroitin ABC lyase on Sepharose CL-6B chromatography, indicating that lead selectively inhibits the synthesis of large and highly charged chondroitin/dermatan sulfate proteoglycans (CS/DSPGs). However, the size of chondroitin/dermatan sulfate chains of the CS/DSPGs was M r≈47 000 in both the control and lead-treated cultures. On the other hand, lead decreased the accumulation of a large CS/DSPG with a core protein of ≈450 kDa in the cell layer and the conditioned medium; the core protein was identified as versican core by Western blot analysis. It is therefore suggested that lead inhibits the synthesis of the versican core protein in vascular smooth muscle cells without a change in length of chondroitin/dermatan sulfate side chains. As a result, versican-poor extracellular matrix would be induced by lead in vascular smooth muscle cells.

Proteoglycan Production by Immortalized Human Chondrocyte Cell Lines Cultured under Conditions That Promote Expression of the Differentiated Phenotype

Large and small proteoglycans are essential components of articular cartilage. How to induce chondrocytes to repair damaged cartilage with normal ratios of matrix components after their loss due to degenerative joint disease has been a major research focus. We have developed immortalized human chondrocyte cell lines for examining the regulation of cartilage-specific matrix gene expression. However, the decreased synthesis and deposition of cartilage matrix associated with a rapid rate of proliferation has presented difficulties for further examination at the protein level. In these studies, proteoglycan synthesis was characterized in two chondrocyte cell lines, T/C-28a2 and tsT/AC62, derived, respectively, from juvenile costal and adult articular cartilage, under culture conditions that either promoted or decreased cell proliferation. Analysis of proteo[35S]glycans by Sepharose CL-4B chromatography and SDS–PAGE showed that the large proteoglycan aggrecan and the small, leucine-rich proteoglycans, decorin and biglycan, were produced under every culture condition studied. In monolayer cultures, a high initial cell density and conditions that promoted proliferation (presence of serum for T/C-28a2 cells or permissive temperature for the temperature-sensitive tsT/AC62 cells) favored cell survival and ratios of proteoglycans expected for differentiated chondrocytes. However, the tsT/AC62 cells produced more proteoglycans at the nonpermissive temperature. Culture of cells suspended in alginate resulted in a significant decrease in proteoglycan production in all culture conditions. While the tsT/AC62 cells continued to produce a larger amount of aggrecan than small proteoglycans, the T/C-28a2 cells lost the ability to produce significant amounts of aggrecan in alginate culture. In addition, our data indicate that immortalized chondrocytes may alter their ability to retain pericellular matrix under changing culture conditions, although the production of the individual matrix components does not change. These findings provide critical information that will assist in the development of a reproducible chondrocyte culture model for the study of regulation of proteoglycan biosynthesis in cartilage.

Macrophage plasma membrane chondroitin sulfate proteoglycan binds oxidized low-density lipoprotein

Lipoprotein interactions with macrophage proteoglycans (PGs) is believed to play an important role in the cellular uptake of lipoproteins and in macrophage cholesterol accumulation. Recently, we have shown the participation of macrophage plasma membrane glycosaminoglycans (GAGs) in the cellular uptake of oxidized LDL (Ox-LDL). The aim of the present study was to identify the specific cell surface proteoglycans involved in this interaction. J-774 A.1 macrophage-like cell line plasma membrane proteoglycans were isolated by anion exchange chromatography from cells that were prelabeled with [ 35S]sodium sulfate. Using Sepharose 6B chromatography, cell surface major proteoglycans were identified as chondroitin sulfate (CS) proteoglycans (77%) and heparan sulfate (HS) proteoglycans (23%). Binding rates of these 35S-labeled proteoglycans to Ox-LDL and to native LDL were analyzed by their ability to bind lipoproteins coupled to a CnBr-activated Sepharose CL-4B chromatography. Of the total labeled cell surface proteoglycans added to the column, 57% were bound to the Sepharose-coupled Ox-LDL, whereas 73% of the cell surface proteoglycans were bound to the Sepharose-coupled native LDL. Binding of the plasma membrane macrophage 35S-labeled proteoglycans to Ox-LDL was inhibited by adding increasing concentrations of non-labeled chondroitin sulfate, or by pretreatment of the 35S-labeled proteoglycans fraction with chondroitinase ABC. In contrast, neither the addition of non-labeled heparan sulfate, nor pretreatment of the labeled proteoglycans fraction with heparinase III, had any significant effect on proteoglycan binding to Ox-LDL. These findings were further supported by using mutant cells characterized by specific glycosaminoglycan deficiencies. Ox-LDL binding and degradation by mutant 745 CHO cells which are characterized by a deficiency in both heparan sulfate and chondroitin sulfate, was decreased by 28 and 27% respectively, compared to the binding of Ox-LDL to the wild-type CHO cells. Ox-LDL binding and degradation by mutant 677 CHO cells, which lack heparan sulfate but have increased levels of chondroitin sulfate, however, was found to be increased by 29 and 19%, respectively, compared to Ox-LDL binding to the wild-type CHO cells. Finally, analysis of the cell surface proteoglycans in macrophages that were subjected to oxidative stress, by their preincubation with angiotensin II, exhibited a 51–59% increase in their cell surface proteoglycan content, with a major effect on chondroitin sulfate proteoglycans. The present study thus demonstrated that Ox-LDL can specifically bind to macrophage surface chondroitin sulfate proteoglycans, and the macrophage content of this proteoglycan is increased under oxidative stress. The interaction between macrophage chondroitin sulfate proteoglycans and Ox-LDL can contribute to enhanced uptake of Ox-LDL with the formation of cholesterol-loaded foam cells, and accelerated atherosclerosis.

Purification and properties of two intracellular aminopeptidases produced by Brevibacterium linens SR3

Two aminopeptidases, designated as aminopeptidase I (API) and aminopeptidase II (APII), were isolated from the disrupted cells of Brevibacterium linens SR3 and purified to homogeneity by a combination of Phenyl-Sepharose, DEAE-Sepharose, Q-Sepharose and Sepharose CL-6B chromatography. Optimal temperature for enzymatic activity was 45°C for API and 37°C for APII, and the pH optimum was found to be 8.5 for API and 8.0 for APII. Divalent metals ions like Co2+ and Ni2+ increased enzymatic activity while Ca2+, Cu2+ and Fe2+ had an inhibitory effect. The enzymes were strongly inhibited by EDTA, 1,10-Phenantroline and cysteine, indicating that both aminopeptidases were metalloenzymes. The Km values of API and APII for l-leucine-p-nitroanilide were 1.0 and 0.25 mm, respectively. Native molecular masses of aminopeptidases I and II were 80 and 220 kDa after gel filtration chromatography while molecular masses of 14 and 18 kDa, were seen, after SDS-polyacrylamide gel electrophoresis.

Cell Density-dependent Regulation of Proteoglycan Synthesis by Transforming Growth Factor-β1 in Cultured Bovine Aortic Endothelial Cells

The regulation of vascular endothelial cell behavior during angiogenesis and in disease by transforming growth factor-beta(1) (TGF-beta(1)) is complex, but it clearly involves growth factor-induced changes in extracellular matrix synthesis. Proteoglycans (PGs) synthesized by endothelial cells contribute to the formation of the vascular extracellular matrix and also influence cellular proliferation and migration. Since the effects of TGF-beta(1) on vascular smooth muscle cell growth are dependent on cell density, it is possible that TGF-beta(1) also directs different patterns of PG synthesis in endothelial cells at different cell densities. In the present study, dense and sparse cultures of bovine aortic endothelial cells were metabolically labeled with [(3)H]glucosamine, [(35)S]sulfate, or (35)S-labeled amino acids in the presence of TGF-beta(1). The labeled PGs were characterized by DEAE-Sephacel ion exchange chromatography and Sepharose CL-4B molecular sieve chromatography. The glycosaminoglycan M(r) and composition were analyzed by Sepharose CL-6B chromatography, and the core protein M(r) was analyzed by SDS-polyacrylamide gel electrophoresis, before and after digestion with papain, heparitinase, or chondroitin ABC lyase. These experiments indicate that the effect of TGF-beta(1) on vascular endothelial cell PG synthesis is dependent on cell density. Specifically, TGF-beta(1) induced an accumulation of small chondroitin/dermatan sulfate PGs (CS/DSPGs) with core proteins of approximately 50 kDa in the medium of both dense and sparse cultures, but a cell layer-associated heparan sulfate PG with a core protein size of approximately 400 kDa accumulated only in dense cultures. Moreover, only in the dense cell cultures did TGF-beta(1) cause CS/DSPG hydrodynamic size to increase, which was due to the synthesis of CS/DSPGs with longer glycosaminoglycan chains. The heparan sulfate PG and CS/DSPG core proteins were identified as perlecan and biglycan, respectively, by Western blot analysis. The present data suggest that TGF-beta(1) promotes the synthesis of both perlecan and biglycan when endothelial cell density is high, whereas only biglycan synthesis is stimulated when the cell density is low. Furthermore, glycosaminoglycan chains are elongated only in biglycan synthesized by the cells at a high cell density.

Purification and some properties of a novel chitosanase from Bacillus subtilis KH1.

One of at least two chitosanases secreted in the culture filtrate of Bacillus subtilis KH1 was purified by two sequential DEAE Sepharose CL-6B chromatographies, followed by Sephacryl S-100 HR gel chromatography. The purified enzyme was homogenous as judged by SDS-PAGE. It showed an estimated molecular weight and pI of 28,000 and 8.3, respectively. The enzyme drastically reduced the viscosity of highly deacetylated chitosan substrates, with the subsequent formation of chitooligosaccharides [(GlcN)(n), n=2-6]. No activity toward carboxymethylcellulose (CMC), chitobiose (GlcN)(2), or chitotriose (GlcN)(3) was detected. Separation and quantification of products of hydrolysis of 10% (w/v) solutions of chitooligosaccharides, (GlcN)(n), n=2-6, by HPLC showed the splitting of (GlcN) (n), n=4-6, in an endo-splitting manner. Oligomers comprising higher units than the starting substrate were also detected, indicating transglycosylation activity. The amino terminal sequence of this enzyme (A-G-L-N-K-D-Q-K-R-R) is identical to that of the chitosanase derived from Bacillus pumilus BN262 and to the deduced amino terminal sequences of Bacillus subtilis 168 and Bacillus amyloliquefaciens UTK chitosanases.

Tyrosinase Activity in Antitumor Compounds of Squid Ink.

Previous studies have demonstrated antitumor activity in squid ink. This study was carried out to clarify the key component of, and the role of tyrosinase in the antitumor activity. The antitumor fraction, which contains illexin-peptidoglycan, soluble melanin and tyrosinase activity, was isolated from the defatted ink using Tris-HCl buffer extraction, DEAE Sephacel and Sephacryl S-300 chromatography. During the isolation procedure, the behavior of the tyrosinase activity exhibited the same pattern as the antitumor activity. The antitumor fraction could be separated by Phenyl Sepharose CL-4B chromatography into three fractions: illexin-peptidoglycan, tyrosinase and the complex of the two. The fraction containing illexin-peptidoglycan and tyrosinase showed the highest activity against the Meth A tumor in BALB/c mice. This suggests that both these components are needed for the antitumor activity of squid ink.