N-terminal Amino Acid Sequence Analysis Research Articles

Cysteine synthase (O-acetylserine (thiol) lyase) substrate specificities classify the mitochondrial isoform as a cyanoalanine synthase.

A cyanoalanine synthase and two isoforms (A, cytosolic and B, chloroplastic) of cysteine synthase (O:-acetylserine (thiol) lyase) were isolated from spinach. N-terminal amino acid sequence analysis of the cyanoalanine synthase gave 100% homology for the determined 12 residues with a published sequence for the mitochondrial cysteine synthase isoform. All three enzymes catalysed both the cysteine synthesis and cyanoalanine synthesis reactions, although with different efficiencies. Michaelis-Menten kinetics were observed for all three enzymes when substrate saturation experiments were performed varying O:-acetylserine, chloroalanine and cysteine. Negative co-operative kinetics were observed for cysteine synthases A and B when substrate saturation experiments were performed varying sulphide and cyanide, compared with the Michaelis-Menten kinetics observed for cyanoalanine synthase. The exception was negative co-operativity observed towards sulphide for cyanoalanine synthase with O:-acetylserine as co-substrate. The optimum sulphide concentration was dependent on the alanyl co-substrate used. The amino acid sequence similarity places these three enzymes in the same gene family, and whilst the close kinetic similarities support this, they also indicate distinct roles for the isoforms.

Determination of the N-Terminal Amino Acid Sequence of the Purified Prothrombin from a Patient with Liver Cirrhosis

The reasons for the decreased functional activity of prothrombin in liver diseases are still speculative. When a highly purified preparation of prothrombin from a patient with liver cirrhosis is available, the cause of prothrombin abnormalities may be researched on a molecular basis. In this study, prothrombin (6.7 mg) was purified from the ascites fluid (1130 mL) of a patient with liver cirrhosis by barium citrate adsorption, ammonium sulfate elution, DEAE Sephacel and Heparin Sepharose CL-6B column chromatography steps. The molecular weight of this prothrombin was the same as that of normal prothrombin purified from a normal plasma pool. The specific activities were found to be 3.36 U/mg in the one stage clotting assay and 28.9 U/mg in the staphylocoagulase/chromogenic substrate assay, while the normal prothrombin specific activities were 3.92 U/mg and 30.1 U/mg respectively. When N-terminal amino acid sequence analysis was carried out, it was seen that the first 20 residues were identical to the normal human prothrombin excepting the Gla at position #14.

Covalently bound flavin in the NqrB and NqrC subunits of Na +-translocating NADH-quinone reductase from Vibrio alginolyticus

Na +-translocating NADH-quinone reductase (NQR) from the marine bacterium Vibrio alginolyticus is composed of six subunits (NqrA to NqrF). On SDS–PAGE of the purified complex, NqrB and NqrC subunits were found to give yellow–green fluorescent bands under UV illumination. Both the NqrB and NqrC, electroeluted from the gel, had an absorption maximum at 448 nm, and the fluorescence excitation maxima at 365 and 448 nm and the emission maximum at 514 nm. The electroeluted NqrB and NqrC, respectively, were identified from their N-terminal amino acid sequences. These results clearly indicated that the NqrB and NqrC subunits have covalently bound flavins. The two subunits were digested by protease and then the fluorescent peptide fragments were separated by a reversed-phase high performance liquid chromatography. N-Terminal amino acid sequence analyses of the fluorescent peptides revealed that the flavin is linked to Thr-235 in the NqrB and Thr-223 in the NqrC subunits. This is the first example that the flavin is linked to a threonine residue. The amino acid sequence around the flavin-linked threonine was well conserved between NqrB and NqrC. Identification of the flavin group is in progress.

Purification and Characterization of Glutathione S-Transferases from the German Cockroach, Blattella germanica (L.)

Glutathione S-transferases (GSTs) were purified and isolated from male adults of the German cockroach, Blattella germanica, by using a three-step procedure involving ammonium sulfate fractionation, glutathione-agarose affinity chromatography, and native polyacrylamide gel electrophoresis. Adult males possessed three GST isozymes, namely GST-1, GST-2, and GST-3, all of which were homodimers with a subunit molecular weight of 25,500. The affinity-purified GSTs had an apparent Km value of 0.16 mM and a Vmax of 78.4 μmol/min/mg protein (toward CDNB). The purified transferases were inhibited by dicumarol, ellagic acid, quercetin, ethacrynic acid, and triphenyltin chloride, showing I50 values (toward CDNB) of 1.6 μM, 7.3 μM, 2.0 μM, 0.35 μM, and 40 nM, respectively. These enzymes were particularly active toward CDNB compared with DCNB and p-nitrophenyl acetate, but had no activity toward 4-nitrobenzyl chloride, 1,2-epoxy-3-(p-nitrophenoxy) propane, trans-4-phenyl-3-buten-2-one, and ethacrynic acid. N-terminal amino acid sequence analysis of GST-1 indicated that the residues Tyr-4 and Leu-6 were highly conserved among 19 other GST sequences from various insect species. Immunological studies with enzyme-linked immunosorbent assay revealed that all three GST isozymes exhibited serum IgE antibody binding activity, indicating the allergenic nature of the enzymes.

Purification and characterization of a novel UV lesion-specific DNA glycosylase/AP lyase from Bacillus sphaericus

The purification and characterization of a pyrimidine dimer-specific glycosylase/AP lyase from Bacillus sphaericus (Bsp-pdg) are reported. Bsp-pdg is highly specific for DNA containing the cis–syn cyclobutane pyrimidine dimer, displaying no detectable activity on oligonucleotides with trans–syn I, trans–syn II, (6–4), or Dewar photoproducts. Like other glycosylase/AP lyases that sequentially cleave the Nglycosyl bond of the 5′ pyrimidine of a cyclobutane pyrimidine dimer, and the phosphodiester backbone, this enzyme appears to utilize a primary amine as the attacking nucleophile. The formation of a covalent enzyme–DNA imino intermediate is evidenced by the ability to trap this protein–DNA complex by reduction with sodium borohydride. Also consistent with its AP lyase activity, Bsp-pdg was shown to incise an AP site-containing oligonucleotide, yielding β- and δ-elimination products. N-terminal amino acid sequence analysis of this 26 kDa protein revealed little amino acid homology to any previously reported protein. This is the first report of a glycosylase/AP lyase enzyme from Bacillus sphaericus that is specific for cis–syn pyrimidine dimers.

Liver transplantation as rescue treatment in a patient with primary AL kappa amyloidosis

Although involvement of the liver is common in systemic amyloidosis, clinical manifestations of hepatic dysfunction and liver biochemical abnormalities are often absent or only mild. Here we report on a patient with primary amyloidosis and rapid development of liver failure, who was successfully treated by liver transplantation. The patient is a 61-year-old Swedish man who was admitted to the local hospital for spontaneous rupture of the spleen. Before admission, he had suffered from diffuse upper abdominal discomfort, diminished appetite, and had lost 15 kg in 6 months. Shortly after splenectomy, he developed cholestatic liver failure with moderate hepatomegaly, jaundice, ascites and hyponatremia. Over a period of 3 weeks his liver failure progressed, renal function deteriorated rapidly, and he developed encephalopathy. Liver transplantation was performed on the 35th day after splenic rupture. Histological examination revealed extensive deposits of amyloid in the spleen and liver. N-terminal amino acid sequence analysis of the amyloid protein, purified from the patient's native liver, revealed an AL protein of kappa I-type origin. The postoperative course was uncomplicated, apart from one episode of sepsis and one course of treatment for acute rejection. He was discharged from hospital with normal liver function and good kidney function. One year after surgery, he was in good condition, with normal liver function. However, a liver biopsy taken at the same time showed de novo amyloid deposits in the grafted liver. We conclude that liver transplantation may be indicated as a life-saving procedure in rapidly progressing hepatic amyloidosis with cholestatic jaundice, although the underlying disease has not changed.

Efficient heterologous expression in Aspergillus oryzae of a unique dye-decolorizing peroxidase, DyP, of Geotrichum candidum Dec 1.

Efficient expression of the dye-decolorizing peroxidase, DyP, from Geotrichum candidum Dec 1 in Aspergillus oryzae M-2-3 was achieved by fusing mature cDNA encoding dyp with the A. oryzae alpha-amylase promoter (amyB). The activity yield of the purified recombinant DyP (rDyP) was 42-fold compared with that of the purified native DyP from Dec 1. No exogenous heme was necessary for the expression of rDyP in A. oryzae. From the N-terminal amino acid sequence analyses of native DyP and rDyP, the absence of a histidine residue in both DyPs, which was considered to be important for heme binding of DyP, was confirmed. These results suggest that rDyP without a typical heme-binding region produced by A. oryzae exhibits a function similar to that of native DyP.

Two phospholipase A2 inhibitors from the plasma of Cerrophidion (Bothrops) godmani which selectively inhibit two different group-II phospholipase A2 myotoxins from its own venom: isolation, molecular cloning and biological properties

Myotoxic phospholipases A(2) (PLA(2)s; group II) account for most of the muscle-tissue damage that results from envenomation by viperid snakes. In the venom of the Godman's viper (Cerrophidion godmani, formerly Bothrops godmani), an enzymically active PLA(2) (myotoxin I) and an inactive, Lys-49 variant (myotoxin II) induce extensive muscle damage and oedema. In this study, two distinct myotoxin inhibitor proteins of C. godmani, CgMIP-I and CgMIP-II, were purified directly from blood plasma by selective binding to affinity columns containing either myotoxin I or myotoxin II, respectively. Both proteins are glycosylated, acidic (pI=4) and composed of 20-25-kDa subunits that form oligomers of 110 kDa (CgMIP-I) or 180 kDa (CgMIP-II). In inhibition studies, CgMIP-I specifically neutralized the PLA(2) and the myotoxic, oedema-forming and cytolytic activities of myotoxins I, whereas CgMIP-II selectively inhibited the toxic properties of myotoxin II. N-terminal amino acid sequence analysis and sequencing of cDNAs encoding the two inhibitors revealed that CgMIP-I is similar to gamma-type inhibitors, which share a pattern of cysteine residues present in the Ly-6 superfamily of proteins, whereas CgMIP-II shares sequence identity with alpha-type inhibitors that contain carbohydrate-recognition-like domains, also found in C-type lectins and mammalian PLA(2) receptors. N-terminal sequencing of myotoxin I revealed a different primary structure from myotoxin II [De Sousa, Morhy, Arni, Ward, Díaz and Gutiérrez (1998) Biochim. Biophys. Acta 1384, 204-208], which provides insight into the nature of such pharmacological specificity.

Liver transplantation as rescue treatment in a patient with primary AL kappa amyloidosis

Abstract Although involvement of the liver is common in systemic amyloidosis, clinical manifestations of hepatic dysfunction and liver biochemical abnormalities are often absent or only mild. Here we report on a patient with primary amyloidosis and rapid development of liver failure, who was successfully treated by liver transplantation. The patient is a 61-year-old Swedish man who was admitted to the local hospital for spontaneous rupture of the spleen. Before admission, he had suffered from diffuse upper abdominal discomfort, diminished appetite, and had lost 15 kg in 6 months. Shortly after splenectomy, he developed cholestatic liver failure with moderate hepatomegaly, jaundice, ascites and hyponatremia. Over a period of 3 weeks his liver failure progressed, renal function deteriorated rapidly, and he developed encephalopathy. Liver transplantation was performed on the 35th day after splenic rupture. Histological examination revealed extensive deposits of amyloid in the spleen and liver. N-terminal amino acid sequence analysis of the amyloid protein, purified from the patient's native liver, revealed an AL protein of kappa I-type origin. The postoperative course was uncomplicated, apart from one episode of sepsis and one course of treatment for acute rejection. He was discharged from hospital with normal liver function and good kidney function. One year after surgery, he was in good condition, with normal liver function. However, a liver biopsy taken at the same time showed de novo amyloid deposits in the grafted liver. We conclude that liver transplantation may be indicated as a life-saving procedure in rapidly progressing hepatic amyloidosis with cholestatic jaundice, although the underlying disease has not changed.

Purification and characterization of a mannan-binding lectin specifically expressed in corms of saffron plant (Crocus sativus L.).

Despite the economical interest of Crocus sativus, its biochemistry has been poorly studied. Herein, we have isolated a lectin present in saffron corm by gel-filtration, anion-exchange, and reversed-phase chromatography. One- and two-dimensional PAGE, MALDI-MS, and N-terminal amino acid sequence analyses indicated that the native protein forms noncovalently linked aggregates of about 80 kDa apparent molecular mass, mainly composed of two charged heterogeneous (pI's, 6.69-6.93) basic subunits of approximately 12 kDa. Their N-terminal sequences shared 25% similarity and were homologous to the N- and C-terminal domains of monocotyledonous mannose-binding lectins, respectively. An additional polypeptide of around 28 kDa apparent molecular mass was also detected, probably corresponding to a precursor processed into two mature subunits. In addition, the N-terminal domain subunit exhibited 56% similarity with curculin, a sweet protein with taste-modifying activity. The native lectin specifically interacts with a yeast mannan and is a major corm protein specifically expressed in this organ.

Lysine 2,3-aminomutase from Clostridium subterminale SB4: mass spectral characterization of cyanogen bromide-treated peptides and cloning, sequencing, and expression of the gene kamA in Escherichia coli.

Lysine 2,3-aminomutase (KAM, EC 5.4.3.2.) catalyzes the interconversion of L-lysine and L-beta-lysine, the first step in lysine degradation in Clostridium subterminale SB4. KAM requires S-adenosylmethionine (SAM), which mediates hydrogen transfer in a mechanism analogous to adenosylcobalamin-dependent reactions. KAM also contains an iron-sulfur cluster and requires pyridoxal 5'-phosphate (PLP) for activity. In the present work, we report the cloning and nucleotide sequencing of the gene kamA for C. subterminale SB4 KAM and conditions for its expression in Escherichia coli. The cyanogen bromide peptides were isolated and characterized by mass spectral analysis and, for selected peptides, amino acid and N-terminal amino acid sequence analysis. PCR was performed with degenerate oligonucleotide primers and C. subterminale SB4 chromosomal DNA to produce a portion of kamA containing 1,029 base pairs of the gene. The complete gene was obtained from a genomic library of C. subterminale SB4 chromosomal DNA by use of DNA probe analysis based on the 1,029-base pair fragment. The full-length gene consisted of 1,251 base pairs specifying a protein of 47,030 Da, in reasonable agreement with 47, 173 Da obtained by electrospray mass spectrometry of the purified enzyme. N- and C-terminal amino acid analysis of KAM and its cyanogen bromide peptides firmly correlated its amino acid sequence with the nucleotide sequence of kamA. A survey of bacterial genome databases identified seven homologs with 31 to 72% sequence identity to KAM, none of which were known enzymes. An E. coli expression system consisting of pET 23a(+) plus kamA yielded unsatisfactory expression and bacterial growth. Codon usage in kamA includes the use of AGA for all 29 arginine residues. AGA is rarely used in E. coli, and arginine clusters at positions 4 and 5, 25 and 27, and 134, 135, and 136 apparently compound the barrier to expression. Coexpression of E. coli argU dramatically enhanced both cell growth and expression of KAM. Purified recombinant KAM is equivalent to that purified from C. subterminale SB4.

Biochemical characterization of sialoprotein “anti‐agglutinin” purified from boar epididymal and seminal plasma

Sialoprotein “anti-agglutinin,” previously shown to inhibit sperm head-to-head agglutination, is found in both boar epididymal and seminal plasma. The present report characterizes anti-agglutinin by mass spectrometry, by N-terminal amino acid sequence analysis, and by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) and Western blotting techniques to assess phosphate content of the molecule. Anti-agglutinin had the SDS-PAGE mobility of approximately 25 kDa. By electrospray ionization-mass spectrometry, however, mass spectra of anti-agglutinin were characterized by two major peaks (19,379–19,382 Da and 19,395–19,397 Da) and several minor peaks. Mass spectrometry of tryptic peptide fragments of deglycosylated anti-agglutinin and amino acid sequence analysis revealed that the protein has a unique peptide-mass fingerprinting of fragments (12,668 Da, 5,209 Da, 1,226 Da, and 1,168 Da) and a novel N-terminal amino acid sequence (KTDDY AISGA KEEEF YDYME ELYAV), respectively. Additionally Western blot techniques, using commercially available monoclonal antibodies, were used to detect presence of phosphothreonine and phosphoserine substituents, but two different monoclonal antibodies did not detect phosphotyrosine. Moreover, treatment with two different alkaline phosphotases converted the molecule, as assessed by SDS-PAGE and detection by silver stain, from the parent form of about 25 kDa to forms of approximately 19 kDa (similar to that assigned by mass spectrometry) and/or 15 kDa. Original antiserum generated toward, and reacting with native anti-agglutinin, reacted only with 19 kDa form. These results are consistent with the conclusion that the native anti-agglutinin may be a novel protein that is phosphorylated at serine and/or threonine residues. Mol. Reprod. Dev. 55:96–103, 2000. © 2000 Wiley-Liss, Inc.

Functional reconstitution of an active recombinant human chymase from Pichia pastoris cell lysate.

We have previously reported efficient production of mature human chymase (h-chymase) using an original system of expression in Pichia pastoris (Nakakubo et al., 2000), whereby recombinant h-chymase (rh-chymase) was secreted as a mature form with the correct N-terminal amino acid sequence and was easily purified. In the course of investigation of secretory rh-chymase, we also found large amounts of chymase to be present in insoluble form in the transformant cell. Although the cellular rh-chymase had no proteolytic activity, its chymotryptic activity was restored in a reconstitution process utilizing guanidine and glutathione. As with secretory rh-chymase, efficient purification was possible by heparin affinity chromatography. The purified cellular rh-chymase showed the same mobility as secretory rh-chymase in sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) before and after deglycosylation. N-terminal amino acid sequence analysis revealed that the signal peptide had been correctly removed. K(m) value (5.93 mM), as well as pH profile and inhibition profile toward protease inhibitors of reconstituted cellular rh-chymase, indicated that the rh-chymase enzymatically closely resembles native h-chymase. Furthermore, it showed a greatly restricted proteolytic activity towards Ang I, and formed Ang II without the further cleavage which is a feature of h-chymase. It was thus found that the insoluble rh-chymase stored in the cells could be solubilized and reconstituted to give the same structure as h-chymase, not only in terms of enzyme active site but also of substrate recognition site.

Biochemical characterization of sialoprotein ?anti-agglutinin? purified from boar epididymal and seminal plasma

Sialoprotein "anti-agglutinin," previously shown to inhibit sperm head-to-head agglutination, is found in both boar epididymal and seminal plasma. The present report characterizes anti-agglutinin by mass spectrometry, by N-terminal amino acid sequence analysis, and by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) and Western blotting techniques to assess phosphate content of the molecule. Anti-agglutinin had the SDS-PAGE mobility of approximately 25 kDa. By electrospray ionization-mass spectrometry, however, mass spectra of anti-agglutinin were characterized by two major peaks (19,379-19,382 Da and 19,395-19,397 Da) and several minor peaks. Mass spectrometry of tryptic peptide fragments of deglycosylated anti-agglutinin and amino acid sequence analysis revealed that the protein has a unique peptide-mass fingerprinting of fragments (12,668 Da, 5,209 Da, 1,226 Da, and 1,168 Da) and a novel N-terminal amino acid sequence (KTDDY AISGA KEEEF YDYME ELYAV), respectively. Additionally Western blot techniques, using commercially available monoclonal antibodies, were used to detect presence of phosphothreonine and phosphoserine substituents, but two different monoclonal antibodies did not detect phosphotyrosine. Moreover, treatment with two different alkaline phosphotases converted the molecule, as assessed by SDS-PAGE and detection by silver stain, from the parent form of about 25 kDa to forms of approximately 19 kDa (similar to that assigned by mass spectrometry) and/or 15 kDa. Original antiserum generated toward, and reacting with native anti-agglutinin, reacted only with 19 kDa form. These results are consistent with the conclusion that the native anti-agglutinin may be a novel protein that is phosphorylated at serine and/or threonine residues.

Isolation of the components of progenitor toxin produced by Clostridium botulinum type C strain Stockholm.

Clostridium botulinum type C strain Stockholm (C-St) produced two types of progenitor toxins (M and L). The purified L toxin consisted of neurotoxin (NT), nontoxic-nonhemagglutinin (NTNHA) and hemagglutinin (HA) components which could be separated into four subcomponents, HA-33, HA-17, HA-22-23 and HA-55. On the other hand, purified M toxin lacked HA components. We isolated all components from the progenitor L toxin by following chromatographic methods. The L toxin was separated into an NT and NTNHA/HAs complex via Mono Q anion exchange column chromatography. Using gel filtration with a TSK-gel HW-55S column in the presence of 6M guanidine hydrochloride, the NTNHA/HAs complex derived from the L toxin could be separated into three fractions, NTNHA single component, HA-55/33 mixture and HA-22-23/17 mixture. Then, the HA-55/33 mixture was separated into each component using Mono S cation exchange column chromatography in the presence of 8M urea. The HA-22-23/17 mixture was also separated from each other with Superose 12 gel filtration column chromatography in the presence of 8M urea. The separated NT, NTNHA and HA subcomponents were homogenous on SDS-PAGE, and were identified to be C-St progenitor toxin gene products based on their N-terminal amino acid sequence analysis. This study presents for the first time an attempt to isolate components from the progenitor toxin. Although reassociation of the isolated components was also attempted via mixing of NTNHA, HA-55, HA-33, HA-22-23 and HA-17, HA activity of the mixture was lower than that of parent NTNHA/HAs complex.

The engL gene cluster of Clostridium cellulovorans contains a gene for cellulosomal manA.

A five-gene cluster around the gene in Clostridium cellulovorans that encodes endoglucanase EngL, which is involved in plant cell wall degradation, has been cloned and sequenced. As a result, a mannanase gene, manA, has been found downstream of engL. The manA gene consists of an open reading frame with 1,275 nucleotides encoding a protein with 425 amino acids and a molecular weight of 47, 156. ManA has a signal peptide followed by a duplicated sequence (DS, or dockerin) at its N terminus and a catalytic domain which belongs to family 5 of the glycosyl hydrolases and shows high sequence similarity with fungal mannanases, such as Agaricus bisporus Cel4 (17.3% identity), Aspergillus aculeatus Man1 (23.7% identity), and Trichoderma reesei Man1 (22.7% identity). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and N-terminal amino acid sequence analyses of the purified recombinant ManA (rManA) indicated that the N-terminal region of the rManA contained a DS and was truncated in Escherichia coli cells. Furthermore, Western blot analysis indicated that ManA is one of the cellulosomal subunits. ManA production is repressed by cellobiose.

Purification and Characterization of Phospholipase D from Cabbage Leaves.

Phospholipase D (PLD) was purified from cabbage leaves. The molecular weight of purified PLD was estimated as approximately 73 and 87 kDa by gel filtration using Superdex 200 HR column and, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), respectively. The transphosphatidylation capacity for phosphatidylcholine of this enzyme reached over 90% , and the enzyme's hydrolysis efficiency for phosphatidylcholine was five-fold higher than that for phosphatidylglycerol. These findings indicated that the cabbage PLD efficiently transferred phosphatidylcholine to phosphatidylglycerol. On N-terminal amino acid sequence analysis of the band separated by SDSPAGE, two sequences with differing N-terminus were detected. This N-terminal difference may have been generated by processing during maturation of PLD.

Fibrinogen is a component of a novel lipoprotein particle: Factor H–related protein (FHRP)–associated lipoprotein particle (FALP)

We have previously described a novel lipoprotein particle consisting of phospholipids, apolipoprotein A-I (apoAI), lipopolysaccharide binding protein (LBP) and Factor H-related proteins (FHRP), and we termed these particles FALP (FHRP-associated lipoprotein particles). Highly purified preparations of FALP contain variable amounts of an unidentified polypeptide triplet of Mr ∼85 000 (tp85). Here we report that tp85 represents fragment D of fibrinogen, as confirmed by N-terminal amino acid sequencing and Western blot analysis with an antifibrinogen antibody. The physical association of fibrinogen with other components of FALP in plasma was further confirmed by sandwich ELISA by using monoclonal antibodies against apoAI, FHRP or LBP to capture the particles and polyclonal antifibrinogen as the detecting antibody. Furthermore, affinity chromatography with anti-FHRP-1–specific IgG showed that fibrinogen is co-immunodepleted with FALP and approximately 17% of total plasma fibrinogen are bound to FALP. LBP is a lipid transfer protein that moves lipopolysaccharide (LPS) to a binding site on CD14 or high-density lipoprotein (HDL). To determine whether fibrinogen affects the lipid transfer activity of LBP on FALP, this activity was measured in FALP prepared with and without fibrinogen. Neither activity of LBP was affected by fibrinogen. The abundance of FALP suggests, instead, an effect of FALP on the function or clearance of fibrinogen or fragment D. (Blood. 2000;95:198-204)

Fibrinogen is a component of a novel lipoprotein particle: Factor H–related protein (FHRP)–associated lipoprotein particle (FALP)

AbstractWe have previously described a novel lipoprotein particle consisting of phospholipids, apolipoprotein A-I (apoAI), lipopolysaccharide binding protein (LBP) and Factor H-related proteins (FHRP), and we termed these particles FALP (FHRP-associated lipoprotein particles). Highly purified preparations of FALP contain variable amounts of an unidentified polypeptide triplet of Mr ∼85 000 (tp85). Here we report that tp85 represents fragment D of fibrinogen, as confirmed by N-terminal amino acid sequencing and Western blot analysis with an antifibrinogen antibody. The physical association of fibrinogen with other components of FALP in plasma was further confirmed by sandwich ELISA by using monoclonal antibodies against apoAI, FHRP or LBP to capture the particles and polyclonal antifibrinogen as the detecting antibody. Furthermore, affinity chromatography with anti-FHRP-1–specific IgG showed that fibrinogen is co-immunodepleted with FALP and approximately 17% of total plasma fibrinogen are bound to FALP. LBP is a lipid transfer protein that moves lipopolysaccharide (LPS) to a binding site on CD14 or high-density lipoprotein (HDL). To determine whether fibrinogen affects the lipid transfer activity of LBP on FALP, this activity was measured in FALP prepared with and without fibrinogen. Neither activity of LBP was affected by fibrinogen. The abundance of FALP suggests, instead, an effect of FALP on the function or clearance of fibrinogen or fragment D. (Blood. 2000;95:198-204)

Molecular Cloning of the Arylsulfate Sulfotransferase Gene and Characterization of Its Product from Enterobacter amnigenus AR-37

The gene encoding the Enterobacter amnigenus AR-37 arylsulfate sulfotransferase (ASST) was cloned, sequenced, and expressed in Escherichia coli NM522. Sequencing led to the identification of three contiguous open reading frames (ORFs) on the same strand. Based on amino acid sequence homology, ORF1, ORF2, and ORF3 are designated astA, dsbA, and dsbB, respectively. A multiple sequence alignment revealed conserved regions in ASST. An N-terminal amino acid sequence analysis of the purified ASST from E. coli NM522 (pEAST72) showed that it is subject to N-terminal processing. The specific activity of purified ASST is 436.5 U/mg of protein. The enzyme is a monomeric protein with a molecular mass of 64 kDa. Using phenol as an acceptor substrate, 4-methylumbelliferyl sulfate is the best donor substrate, followed by beta-naphthyl sulfate, p-nitrophenyl sulfate (PNS), and alpha-naphthyl sulfate. For PNS, alpha-naphthol is the best acceptor substrate, followed by phenol, resorcinol, p-acetaminophen, tyramine, and tyrosine. The enzyme has a different acceptor specificity than the enzyme purified from Eubacterium A-44. It is similar to Klebsiella K-36 and Haemophilus K-12. The apparent K(m) values for PNS using phenol as an acceptor and for phenol using PNS as a donor are 0.163 and 0.314 mM, respectively. The pI and optimum pH are 6.1 and 9.0, respectively.