PZ-peptidase Activity Research Articles

A Study of the Collagen-binding Domain of a 116-kDaClostridium histolyticum Collagenase

The Clostridium histolyticum 116-kDa collagenase consists of four segments, S1, S2a, S2b, and S3. A 98-kDa gelatinase, which can degrade denatured but not native collagen, lacks the C-terminal fragment containing a part of S2b and S3. In this paper we have investigated the function of the C-terminal segments using recombinant proteins. Full-length collagenase degraded both native type I collagen and a synthetic substrate, Pz-peptide, while an 88-kDa protein containing only S1 and S2a (S1S2a) degraded only Pz-peptide. Unlike the full-length enzyme, S1S2a did not bind to insoluble type I collagen. To determine the molecular determinant of collagen binding activity, various C-terminal regions were fused to the C terminus of glutathione S-transferase. S3 as well as S2bS3 conferred collagen binding. However, a glutathione S-transferase fusion protein with a region shorter than S3 exhibited reduced collagen binding activity. S3 liberated from the fusion protein also showed collagen binding activity, but not S2aS2b or S2b. S1 had 100% of the Pz-peptidase activity but only 5% of the collagenolytic activity of the full-length collagenase. These results indicate that S1 and S3 are the catalytic and binding domains, respectively, and that S2a and S2b form an interdomain structure.

Expression of PZ-peptidases by cultures of several pathogenic fungi. Purification and characterization of a collagenase from Trichophyton schoenleinii.

Peptidolytic activity was studied in the broken-cell extracts of 17 isolates of pathogenic fungi tested with phenylazobenzyloxycarbonyl-Pro-Leu-Gly-Pro-Arg (PZ-PLGPA) as a substrate. All the fungi studied except Candida spp., Cryptococcus neoformans and two actinomycetes hydrolyzed the substrate and therefore contained a so-called PZ-peptidase activity. Of all the positive strains, Trichophyton schoenleinii, a pathogenic fungus showed the highest activity and was therefore chosen as a source for PZ-peptidase purification. The four chromatographic steps, a 'negative' dye column, a 'positive' dye column, hydroxyapatite Ultrogel, and modified TSK (HW 55), gave a highly purified peptidase with a 12% overall yield. Inhibitor studies suggested that the 82 000 M(r) PZ-peptidase is a metalloproteinase. Moreover it cleaved native rat type I collagen. Partial peptide sequencing showed a strong sequence homology to regions of two metalloproteinases previously identified in the yeast Saccharomyces cerevisiae and in rat.

Isolation and characterization of Pz-peptidase from Bacillus licheniformis N22

Pz-peptidase is an endopeptidase that cleaves the synthetic substrate, 4-phenylazobenzyloxycarbonyl-Pro-Leu-Gly-Pro-Arg (Pz-peptide), which was originally developed for the assay of Clostridium histolyticum collagenase (Wünsch and Heidrich, Hoppe-Seyler's Z. Physiol. Chem., 333, 149–151, 1963; Morales and Woessner, J. Biol. Chem., 252, 4855–4860, 1977). Pz-peptidase was purified from the culture filtrate of Bacillus licheniformis N22. The purified Pz-peptidase showed a molecular weight of 70,000 in SDS-polyacryl-amide gel electrophoresis and 150,000 in gel filtration. Optimal pH for cleavage of Pz-peptide was 7.8. The Pz-peptidase activity was strongly inhibited by metal chelators such as EDTA and O-phenanthroline. Substrate specificity studies indicated that Pz-peptidase cleaved oligopeptides at the Xaa-Gly site in Xaa-Gly-Pro. However, Pz-peptidase failed to hydrolyze native collage, denatured collagen, hemoglobin and casein.

High-performance liquid chromatographic determination of PZ-peptidase activity

A rapid and sensitive assay method for the determination of PZ-peptidase activity is reported. This method is based on the monitoring of the absorption at 320 nm of 4-phenylazobenzyloxycarbonyl- l-Pro- l-Leu (PZ-Pro-Leu), enzymatically formed from the substrate 4-phenylazobenzyloxycarbonyl- l-Pro- l-Leu-Gly- l-Pro- d-Arg (PZ-peptide), after separation by high-performance liquid chromatography using a C 18 reversed-phase column by isocratic elution. This method is sensitive enough to measure PZ-Pro-Leu at levels as low as 10 pmol, yields highly reproducible results and requires less than 5.5 min per sample for separation and determination. The optimum pH for PZ-peptidase activity was 7.5–8.0. The K m and V max values were 166.7 μ M and 5.35 pmol/min·μg protein, respectively, with the use of enzyme extract obtained from mouse whole brain. The approximate molecular mass of this enzyme was estimated to be 64 000 by gel filtration. PZ-peptidase activity was strongly inhibited by Zn 2+, Cu 2+ and p-chloromercuriphenylsulphonic acid. By using this method, PZ-peptidase activity could be readily detected in a single mouse pituitary gland. Among the tissues examined in various mouse brain regions, the highest specific activity of the enzyme was found in cerebral cortex. The sensitivity and selectivity of this method will aid in efforts to examine the physiological role of this peptidase.

Purification and characterization of Pz-peptidase from rabbit muscle

Pz-peptidase was purified from rabbit muscle by acid precipitation of tissue homogenate followed by cation- and anion-exchange chromatography, gel chromatography, and immunoadsorption. In analytical gel chromatography, one single peak of protein with corresponding Pz-peptidase activity was obtained. The enzyme had an apparent M r of 74,000 in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and was eluted at pH 4.8 in chromatofocusing. No metals were detectable in the protein by neutron activation analysis. Purified Pz-peptidase hydrolyzed Dnp-Pro-Leu-Gly-Pro-Trp- d-Lys ( K m 7.2 μ m) most effectively in the presence of 5 m m 2-mercaptoethanol and 10 m m CaCl 2. No inhibition was observed with inhibitors of serine proteinases, aspartic proteinases, or metalloproteinases, apart from some nonspecific reversible inhibition by 1,10-phenan-throline. The activation by Ca 2+ was reversed by EDTA. The enzyme was not inhibited by E-64, cystatin, or leupeptin, but was irreversibly inactivated by iodoacetate, iodoacetamide, and N-ethylmaleimide. It was therefore concluded that rabbit muscle Pz-peptidase is not a typical member of any of the four recognized catalytic classes of proteinases, but may be an atypical cysteine endopeptidase. The peptidase was not bound by α 2-macroglobulin. No hydrolysis of gelatin or fibronectin by the enzyme was detected, nor was there any activation of latent collagenase.

A continuous fluorimetric assay for clostridial collagenase and Pz-peptidase activity

The peptide derivative N alpha-(2,4-dinitrophenyl)-L-prolyl-L-leucyl-glycyl-L-prolyl-L-tryptophanyl-D- lysine (Dnp-Pro-Leu-Gly-Pro-Trp-D-Lys) has been found to be a convenient substrate for the assay of clostridial collagenase and Pz-peptidase. The substrate shows a 25-fold enhancement of fluorescence (gamma ex. 283 nm, lambda em. 350 nm) following hydrolysis of the Leu2-Gly3 peptide bond. The value of Km for clostridial collagenase was 17 microM. The substrate for the first time makes possible continuous fluorimetric assays for Pz-peptidase and clostridial collagenase.

Effect of chlorpromazine on pz-peptidase and several other peptidase activities in cloned osteoblastic cells (MC3T3-E1)

The effect of chlorpromazine (CPZ) on the degradation of collagen and non-collagenous peptides in clonal osteoblastic MC3T3-E1 cells was investigated by measuring the activities of PZ-peptidase, collagenase-like peptidase (CL-peptidase), dipeptidyl-aminopeptidase (DAP), leucine aminopeptidase (LAP) (EC 3.4.11.1), and post-proline cleaving enzyme (PPCE) (EC 3.4.21.26). CPZ increased PZ-peptidase and CL-peptidase activities in a dose-related fashion, but it had no effect on LAP and PPCE activities in the cells. CPZ (10 μg/ml) enhanced the specific activities of PZ-peptidase, CL-peptidase, and DAP for 72 hr after the start of CPZ stimulation; in particular, about a 3.3-fold increase of PZ-peptidase activity was observed at 12 hr of culture. Furthermore, other phenothiazine derivatives specifically enhanced the PZ-peptidase, CL-peptidase, and DAP activities as well as CPZ. Since PZ-peptidase, CL-peptidase, and DAP, involved in the degradation of collagen peptides, were induced significantly by CPZ (and/or other phenothiazine derivatives) in comparison with LAP and PPCE, involved in the degradation of non-collagenous peptides, these results show that CPZ specifically stimulated collagen catabolism by inducing the collagen-catabolizing enzymes. In addition, CPZ specifically inhibited collagen synthesis in clonal osteoblasts.

PZ-peptidase activity from ejaculated boar spermatozoa

Protein constituents of the boar spermatozoon were fractionated in three components, the hypotonic soluble fraction, the detergent-soluble fraction, and the detergent-insoluble fraction. When all these fractions were assayed spectrophotometrically using the PZ-peptide as substrate, a high value of PZ-peptidase specific activity was observed in the first fraction. Electrophoretic analysis at pH 8.3 of the protein content from the hypotonic soluble fraction revealed the existence of multiple molecular forms capable of hydrolysing the PZ-peptide. The major form was characterized by a surprisingly high value of electrophoretic mobility, index of the presence of numerous negatively charged residues. Biochemical and ultrastructural analyses showed that the hypotonic soluble fraction did not contain intrinsic, and specifically acrosomal, sperm enzymes.

Type III procollagen peptide and PZ-peptidase serum levels in pre-cirrhotic liver diseases

To obtain a dynamic and non-invasive picture of hepatic fibrosis in pre-cirrhotic liver diseases we measured both the concentration of the N-terminal peptide of procollagen III, as a marker of collagen synthesis, and the activity of PZ-peptidase, an enzyme involved in collagen degradation, in the serum of alcoholic or chronic viral hepatitis patients. Peptide serum levels were similar in chronic persistent hepatitis and controls, but significantly higher in chronic active hepatitis. Chronic persistent hepatitis patients had PZ-peptidase levels higher than controls, but similar to chronic active hepatitis. The increase in collagen synthesis without a parallel increase in collagen degradation seen in chronic active hepatitis could be regarded as a sign of impending cirrhosis, whereas the unbalanced rise in PZ-peptidase observed in chronic persistent hepatitis is consistent with the non-progressive character of this disorder. In alcoholic hepatitis both peptide concentration and PZ-peptidase activity were elevated, thus suggesting that both collagen synthesis and degradation are activated. However, the greater increase in PZ-peptidase than in peptide serum levels seen in some patients seems to indicate a minor tendency to progressive fibrosis or a trend towards resolution. Unlike liver disease patients, normal peptide and PZ-peptidase levels were found in patients with pancreatic fibrosis. Since circulating inhibitors and activators of the PZ-peptidase activity can be excluded, as proved by this study, joint peptide and PZ-peptidase serum measurements would seem to offer a simple reliable non-invasive method for differentiating and monitoring progressive and non-progressive forms of hepatic fibrosis.

Highly sensitive assay for PZ-peptidase activity by high-performance liquid chromatography

A rapid and highly sensitive assay method for measuring PZ-peptidase activity in newborn rat brain is described. The method is based on monitoring the absorption at 320 nm of PZ-Pro-Leu enzymatically formed from the substrate, PZ- l-Pro- l-Leu-Gyl- l-Pro- d-Arg, after separation by high-performance liquid chromatography using a reversed-phase column. This method is sensitive enough to measure PZ-pro-Leu at concentrations as low as 5 pmol, and is able to make the column ready for the next injection within 10 min after the preceding injection. By using this method, PZ-peptidase activity was discovered in clonal osteoblastic cells derived from newborn mouse calvaria.

PZ-peptidase activities of some black-pigmented Bacteroides species

Bacteroides gingivalis (both W 83 and ATCC 33277 strains), B. asaccharolyticus (ATCC 25260), and B. melaninogenicus (ATCC 25845) produced hydrolytic activity on the synthetic peptide 4-phenylazobenzyl-oxycarbonyl-L-prolyl-L-leucyl-glycyl-prolyl-D-arginine (PZ peptide) during their early logarithmic phase of growth. The PZ-peptidase activity of the ATCC 25260 strain was the highest with an initial rate of reaction at 0.54 nmol PZ-pro-leu/h per 108 cells. Relatively low levels of PZ peptidase were produced by the pathogenic W 83 cells. In all the strains tested, no further increase in PZ-peptidase activity was detected after the late logarithmic phase, even when the cultures lysed. The result of the protease test seems to indicate that the PZ-peptidase activity of both oral strains of B. gingivalis is collagenase, while that of B. asaccharolyticus may be a mixture of protease and collagenase enzymes.

Isolation and characterization of PZ-peptidase in developing rat brain

Changes in the activity of a collagen peptidase, PZ-peptidase, acting on a synthetic substrate [4-Phenylazobenzyloxycarbonyl(PZ)- l-Pro- l-Leu-Gly- l-Pro- l-Arg] for bacterial collagenase were examined in developing rat brain regions. The hypothalamus, pons-medulla, colliculi, cerebellum, ceerbrum, midbrain and pituitary gland were studied in rats ranging in age from 1 week to adult; PZ-peptidase activity continuously decreased with maturation in all of the brain regions examined except the hypothalamus. The pituitary gland showed the highest activity in all of the brain regions. PZ-peptidase activity in crude mitochondrial and supernatant fractions from rat whole brain had an optimum pH between 7.5–8.0. It was strongly inhibited by p-chloromercuribenzoic acid, N-ethylmaleimide or EDTA. whereas iodoacetic acid did not affect the enzyme activity. Among various metal ions, the enzyme activity was inhibited by Zn +2 or Cu +2 but not by Mn +2, Ca +2, Mg +2 or Na +. There is no inhibition of the activity by serine protease inhibitors, including diisopropylfluorophosphate and phenylmethylsulphonyl fluoride. An approximate molecular weight of this enzyme was estimated to be 68,000 by gel filtration. Since these properties of rat brain PZ-peptidase were similar to those of other peripheral PZ-peptidases, we suppose that PZ-peptidase in the brain may be the same molecule as the enzyme which hydrolyses collagen peptides in peripheral tissues, but it may have some different physiological roles.

Distribution of Pz-peptidase in bovine epididymal and ejaculated semen.

Bovine epididymal or ejaculated semen was fractionated by density gradient centrifugation in Percoll, and seminal components recovered from the gradients were subjected to additional separation and washing steps. This procedure resulted in isolation of four major seminal constituents: particle-free extracellular fluid, washed light particulates, washed cytoplasmic droplets, and washed spermatozoa. When assayed using the Pz-peptide substrate, all the isolated seminal fractions contained substantial Pz-peptidase activity. The extracellular fluid Pz-peptidase was present in soluble form, but Triton X-100 was required for complete extraction of the Pz-peptidase activity from the spermatozoa, cytoplasmic droplets, and light particulates. The greatest Pz-peptidase activities were observed in the cytoplasmic droplet and epididymal sperm extracts, whereas the activities in extracellular fluid, extracts of light particulates, and extracts of ejaculated spermatozoa were relatively low. Most of the Pz-peptidase activity in extracts of epididymal spermatozoa was attributable to cytoplasmic droplets. The specific Pz-peptidase activities found by regression analysis were 6.1 mU/billion attached cytoplasmic droplets and 1.1 mU/billion spermatozoa. These results established that in the bovine, cytoplasmic droplets were the major source of Pz-peptidase activity in semen and that Pz-peptidase was not primarily a spermatozoal enzyme.

Dose-dependent effects in the subacute response of the rat lung to quartz. II. Protease activities and levels of soluble hydroxyproline in lung lavage.

The response of the rat lung to a range of doses of quartz at 50 and 100 days after its administration by intratracheal instillation has been assessed by bronchopulmonary lavage. The effects on the levels of protein and hydroxyproline and on the PZ peptidase and collagenolytic activities of lavage fluid supernatants are described and an assessment of the hydroxyproline content of recovered cells is made. In addition, assays for PZ peptidase and collagenase activity were carried out on polymorph enriched fractions and on samples obtained from short-term culture of recovered macrophages. Both protein and hydroxyproline measurements did show dependence on the amount of quartz instilled and the time after its administration. Measurements of PZ peptidase and collagenase activities suggest that the polymorphonuclear leukocytes, not the macrophages, are the major source of these degradative enzymes. The relevance of these findings with regard to the importance of the PMN in quartz-induced fibrosis, is discussed.

PZ-peptidase activity in the pregnant and non-pregnant human cervix.

PZ-peptidase activity was determined in homogenates of cervical tissue from non-pregnant women, women in late pregnancy and women immediately after delivery. There was a significant increase in activity in late pregnancy and a further increase in post-delivery specimens when compared with non-pregnant tissue. A possible link between rising prostaglandin levels and cervical softening is suggested.

PZ-peptidase activity in human uterine cervix in pregnancy at term

PZ-peptidase (EG 3.4.-) was detected in human uterine cervix distributed in the soluble fraction after 100 000 × g centrifugation. Optimum pH for PZ-peptidase was observed to be pH 7.2–7.4, except for two of the preparations examined. PZ-peptidase activity was found to significantly increase in pregnancy at term as compared with that in a control group.