Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An enzyme immunoassay for the determination of human urinary kallikrein has been developed and is compared with other human urinary kallikrein assays such as radioimmunoassay, dog blood pressure assay, rat uterus test after kinin liberation and synthetic substrate(20) tests (AcPheArgOEt and S-2266). The usable range of the standard curve is from 0.05 to 12 ng kallikrein per test. The intraassay coefficient of variation is between 2 and 4%, the interassay coefficient of variation is between 4 and 12%, and the recovery of authentic kallikrein added to urine samples is 95%. Human saliva and human pancreatic kallikrein show the same binding curves as purified human urinary kellikrein. Kallikrein from urine of rats, dogs and rabbits as well as boar acrosin and pig pancreatic kallikrein, bovine trypsin and chymotrypsin show no cross-reactivity.
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PMID:Enzyme immunoassay of human urinary kallikrein. Determination of human urinary kallikrein, III. 675 55

A proacrosin conversion inhibitor present in boar spermatozoa has been purified and initially characterized. Purification methods included sequential acid extractions of washed spermatozoa at pH 4.0, pH 3.5, and pH 2.5 followed by successive gel filtrations of the pH 2.5 sperm extract supernatant over Sephadex G-75 and G-50. The resulting 8.8-fold purified materials were judged to be homogeneous by sodium dodecyl sulfate-polyacrylamide disc gel electrophoresis, had an estimated molecular weight of 12,800, and a constant specific activity of 65 units/mg. Treatment with the proteinases acrosin, trypsin, or chymotrypsin destroyed the highly purified proacrosin conversion inhibitor, indicating that it is a protein. Additional properties of the inhibitor included stability to long periods of storage at pH 3.0 and 4 degrees C, stability to boiling and lyophilization, and an absolute requirement for divalent cations to maintain activity. The highly purified proacrosin conversion inhibitor does not inhibit acrosin. Therefore, it apparently acts to prevent proacrosin conversion by selectively inhibiting the zymogen's self-catalyzed conversion mechanism.
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PMID:Proacrosin conversion inhibitor. Purification and initial characterization of a boar sperm protein which prevents the conversion of proacrosin into acrosin. 680 Oct 40

A high-molecular-weight form of acrosin (alpha-acrosin, EC 3.4.21.10) was extracted from spermatozoa obtained from frozen semen and purified over 300-fold. Purification was effected by sequential use of Sephadex G-150, CM-cellulose and DEAE-cellulose chromatography. Properties of human acrosin were compared with those of human pancreatic trypsin. The molecular weight (Mr) of acrosin (70000) was greater than that of trypsin (Mr 21000). Isoelectric points for acrosin (pI = 9.0) and trypsin (pI = 8.2) were also different. alpha-N-Benzoyl-L-arginine ethyl ester was hydrolysed 50% more rapidly by acrosin than by trypsin. Acrosin had similar kcat. values for the hydrolysis of esters with different acylating groups (i.e. benzoyl-L-arginine and p-tosyl-L-arginine esters). In contrast, trypsin had dissimilar kcat. values for the hydrolysis of esters with different acylating groups. Kinetic data argue against deacylation as the rate-limiting step in ester hydrolysis by acrosin. Acrosin was less sensitive than trypsin to inhibition by 7-amino-1-chloro-3-L-tosylamidoheptan-2-one ('TLCK'), di-isopropyl fluorophosphate and soya-bean trypsin inhibitor. D-Fructose and D-arabinose inhibited acrosin, but had no effect on trypsin. The data indicate that definite differences exist between human acrosin and trypsin.
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PMID:Characterization of a high-molecular-weight form of human acrosin. Comparison with human pancreatic trypsin. 680 60

Human and bovine spermatozoa have been collected and washed repeatedly with isotonic saline to remove seminal plasma inhibitors and activate the acrosin. Then the acrosin activity of the cells was assayed with alpha-N-Benzoyl-DL-Arg-beta-naphthylamide (BANA). It was found that the surface-bound enzyme was not inhibited by high molecular weight inhibitors of trypsin but was markedly inhibited by low molecular weight trypsin inhibitors. Divalent metals (Zn++, Cu++, Hg++, Co++, Cd++) were all efficient inhibitors of acrosin on the washed cells. It was shown that the removal of zinc or copper from acrosin completely restored activity. It is proposed that the different levels of zinc in the male and female genital tract regulate acrosin activity. Aged cells released a soluble acrosin which was inhibited by serum and seminal plasma inhibitors of trypsin-like enzymes as well as by zinc ions in an identical manner to the surface-bound enzyme.
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PMID:Inhibition of human and bovine sperm acrosin by divalent metal ions. Possible role of zinc as a regulator of acrosin activity. 681 4

A radioimmunoassay for the determination of human urinary kallikrein was developed. The sensitivity of the assay was 0.5 microgram/l. Dose-response curves of human submandibular and parotid saliva, sweat, pancreatic juice and bile paralleled the standard curve obtained with purified human urinary kallikrein. Substances with similar antigenic determinants were also found in human serum, ascites, seminal plasma, amniotic fluid, cervical mucus, tears, liquor and faeces, but not in human breast milk and gastric juice. Moreover, immunoreactive material was detected in the urine of guinea pigs, orangoutangs and chimpanzees, but not in the urine of rats, cats and rabbits. Porcine acrosin and kallikrein, as well as bovine trypsin and chymotrypsin, showed no cross reactivity.
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PMID:Radioimmunoassay of human urinary kallikrein: determination of human urinary kallikrein, II. 690 44

The leech Hirudo medicinalis contains three different groups of proteinase inhibitor proteins, the thrombin-specific hirudin, the bdellins directed against trypsin, plasmin and acrosin, and the eglins which were discovered only recently. We are interested in the eglins mainly for two reasons: (i) They form strong complexes with the granulocytic elastase and cathepsin G with Ki values close to 1 x 10(-10) mol/l. Due to this property they are potential candidates for the therapeutic treatment of various diseases. (ii) Although the eglins do not contain a disulfide bridge to stabilize the tertiary structure, they are highly resistant to denaturation by acidification and by heat as well as to proteolytic degradation.
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PMID:Structure of the elastase-cathepsin G inhibitor of the leech Hirudo medicinalis. 690 12

A series of substituted benzamidines was tested for their inhibitory effects on boar acrosin. Substituents with electron-donating properties and small aliphatic residues increase the inhibitory activity of benzamidine, whereas aromatic residues have only a slight enhancing influence. Only substituents with a beta- or gamma-keto group increase the acrosin binding affinity by more than one order of magnitude. Comparison of the structure-activity relationships for the inhibition of acrosin and trypsin showed differences in the binding sites of both enzymes.
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PMID:Synthetic inhibitors of serine proteinases. 22. Inhibition of acrosin by benzamidine derivatives. 698 41

Previous studies demonstrated that proteolytic activity is associated with isolated rabbit sperm nuclei and is responsible for the degradation of nuclear protamine that occurs during thiol-induced in vitro decondensation of the nuclei (Zirkin and Chang, 1977; Chang and Zirkin, 1978). In this study, we present the results of experiments designed to characterize this proteolytic activity. Basic protein isolated from rabbit sperm nuclei incubated with 5 mM dithiothreitol (DTT) and 1 percent Triton X-100 for increasing periods of time exhibited progressively faster migrating bands on acid-urea polyacrylamide gels, reflection the progressive degradation of protamine. Ultimately, a specific and characteristic peptide banding pattern resulted. When sperm nuclei were treated with the esterase inhibitor nitrophenyl-p-guanidino benzoate (NPGB) to inhibit the nuclear-associated proteolytic activity and then incubated with one of several exogenous proteinases in addition to DTT and Triton X-100, characteristic peptide banding patterns were seen for each exogenous proteinase employed. For trypsin, chymotrypsin, pronase, and papain, the peptide banding patterns differed from one another and from the pattern characteristic of protamine degradation by the nuclear-associated proteinase. By contrast, when rabbit acrosin served as the exogenous proteinase, the peptide banding pattern seen was identical to the pattern characteristic of the nuclear-associated proteinase. These results demonstrate directly that the proteinase associated with rabbit sperm nuclei and involved in sperm nuclear decondensation in vitro is acrosinlike.
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PMID:Involvement of an acrosinlike proteinase in the sulfhydryl-induced degradation of rabbit sperm nuclear protamine. 698 41

Acrosin was extracted from boar sperm and purified by Sephadex gel filtration and affinity chromatography on Phe-Phe-Arg Sepharose 4B in acidic condition. Its enzymic properties were characterized in comparison with trypsin. The oligopeptides with Arg at the carboxy-termini were used as the ligands for affinity chromatography. Phe-Phe-Arg adsorbed acrosin at pH 5 and released in at pH 3. To adsorb acrosin, it was found that the ligand should be longer than tripeptide with Arg in the carboxy-termini. Disc gel electrophoretogram of purified boar acrosin gave a broad band consisted from three fractions which hydrolysed N-alpha-benzoyl-arginine ethylester (BAEE). The pH optimum and inhibition spectra were similar to those of trypsin, however, the influence of urea on them were very different among each other. Calcium ion decreased Km for BAEE, and increased Ki of aprotinin. The kinetic analysis of acrosin for its substrate and products resulted that Km for BAEE was minimal at around pH 8 and maximal at pH 5, on the contrary, Ki of the product was low at pH 5, but progressively increased along the elevation of pH. The same tendency was observed for trypsin. From the attitudes on the affinity chromatographies and the pH profiles of kinetics parameters, it was concluded that the active sites of acrosin and trypsin were similar to each other.
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PMID:Studies on acrosin. I. Purification and characterization of boar acrosin. 702 4

Two trypsin inhibitor types, PII and PI II, were isolated by affinity chromatography of a potato extract on a column of trypsin immobilized on Sepharose 4B. Fraction PI I afforded after ion exchange chromatography on SE-Sephadex two isoinhibitors, PI IA (Mr approximately 18 000; pI approximately 6.3) and PI IB (Mr approximately 19 500; pI approximately 7.2). The chromatography of fraction PI II on SE-Sephadex yielded three inhibitors of approximately equal molecular weight (Mr approximately 13 500), PI IIC (pI approximately 6.3), PI IID (pI approximately 7.7), and PI IIE (pI approximately 9.1). All the inhibitors isolated show a high activity toward trypsin, acrosin, and chymotrypsin. Unlike the two isoinhibitors of PI I, which practically do not inhibit kallikrein, inhibitors PI II show an effect on this enzyme. Neither the isoinhibitors of PI I nor inhibitors PI II are active toward cathepsin D.
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PMID:Polyvalent proteinase inhibitors from potatoes. Isolation and characterization of acrosin inhibitors from Solanum tuberosum. 704 Jan 19


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