Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C1389183 (autodigestion)
 317 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The autodigestion of plasmin in neutral solution at 37 degrees C and prevention of plasmin autodigestion by methylamine were confirmed by using rho-Tosyl-L-Arginine-Methyl ester as a substrate of plasmin. The autodigestion of plasmin was prevented by human plasma alpha2-macroglobulin which has been reported as an antiplasmin of immediate and reversible type but was not prevented by alpha1-antitrypsin which has been reported as an antiplasmin of slow and irreversible type.
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PMID:Prevention of plasmin autodigestion by human plasma alpha2-macroglobulin. 7 56

Leucine beta-naphthylamidase associated with the microvilli membranes of rabbit small intestine was solubilized with papain [EC 3.4.22.2] and purified by Sephadex G-200 gel filtration, DEAE-cellulose column chromatography, passage through a column of Sepharose 4B coupled with anti-sucrase antibodies and preparative disc electrophoresis in polyacrylamide gel. The purified enzyme was homogeneous on ultracentrifugation and disc electrophoresis, but a double immunodiffusion test showed the presence of a minor component which was probably denatured enzyme. The molecular weight of the purified enzyme was estimated to be 225,000 by Sephadex G-200 gel filtration and the sedimentation coefficient (S-0-20, w) was found to be 6.90S. Purified enzyme required bovine serum albumin for maximal activity, perhaps for its protection from autodigestion. It hydrolyzed, in addition to L-leucine beta-naphthylamide, various L-amino acid beta-naphthylamides and dipeptides with a free alpha-amino group, but did not hydrolyze benzoyl-L-arginine beta-naphthylamide. Therefore, the purified enzyme is an aminopeptidase. Hg-2+ and Cu-2+ ions strongly inhibited the enzyme activity, but other metal ions and EDTA showed no or only slight effect. N-Ethylmaleimide exhibited a weak inhibition. Purified enzyme had an optimal pH and Km value for leucine beta-naphthylamide similar to those of enzymes from other sources. Antibodies against the purified enzyme were raised in guinea pigs. The antibodies obtained were found by double immunodiffusion to be specific for the enzyme. They precipitated the enzyme quantitatively and partially inhibited the enzyme activity.
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PMID:Purification and properties of leucine beta-naphthylamidase from rabbit small-intestinal mucosal cells. 23 93

The LexA repressor of Escherichia coli undergoes a specific cleavage reaction in vivo, an event that leads to derepression of the SOS regulon and requires an activated form of RecA protein. In vitro, cleavage requires RecA at neutral pH; at alkaline pH, a spontaneous cleavage reaction termed autodigestion takes place. Both autodigestion and RecA-mediated cleavage cut the same bond, and are observed for the same set of substrates, suggesting that RecA acts indirectly to stimulate LexA self-cleavage at neutral pH, perhaps binding to LexA and acting as an allosteric effector. We previously isolated a set of lexA(Ind-) mutants that are deficient in in vivo RecA-mediated cleavage but retain significant repressor function. Here, we describe the in vitro cleavage of purified mutant proteins. All of those tested were deficient in both cleavage reactions. Although most of them were equally deficient in both reactions, some were more deficient in one reaction than the other. Several mutant proteins appeared to have defects in binding to RecA. Autodigestion of all but one of the poorly cleavable mutant proteins reached a maximum rate at pH around 10, as does wild-type LexA. The exception was KR156, which changed Lys156, a residue previously implicated in the mechanism of cleavage, to Arg, another basic residue: for this protein, the rate of autodigestion increased with pH at values above 11. RecA-mediated cleavage of KR156 was 1% the wild-type rate at pH 7, but increased with increasing pH to a plateau at pH 9.5, where the rate was 40% the wild-type rate. In contrast, an essentially constant rate was observed for wild-type LexA over the pH range 6 to 11. We suggest, first, that deprotonation of Arg156 and, by inference, Lys156 in the wild-type protein, is required for both autodigestion and RecA-mediated cleavage: and second, that RecA acts to reduce the pKa of Lys156, allowing efficient cleavage of wild-type repressor under physiological conditions.
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PMID:Autodigestion and RecA-dependent cleavage of Ind- mutant LexA proteins. 269 34

Human urine urokinase [EC 3.4.21.31] was found to be inactivated by dithiothreitol (DTT) much more severely than by 2-mercaptoethanol at the same concentration on the basis of -SH groups. Removal of DTT by dialysis restored the activities of esterase toward acetyl-glycyl-L-lysine methyl ester, plasminogen activation, and amidase toward 7-(glutaryl-glycyl-L-arginine-amido)-4-methyl coumarin. But the restoration of amidase activity was much less than that of esterase activity. The addition of DTT mediated the conversion of high molecular weight urokinase to low molecular weight urokinase, releasing several peptides. This suggests that the urokinase consists of several polypeptides linked by disulfide bonds. The molecular weight of urokinase produced with DTT was smaller than that of low molecular weight urokinase obtained by autodigestion of high molecular weight urokinase. The autodigestion was also accompanied by liberation of some peptides. But, those peptides released on autodigestion of high molecular weight urokinase were different from those appearing in the presence of DTT.
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PMID:Effect of dithiothreitol on activity and protein structure of human urine urokinase. 399 96

The concentration of bradykinin in human plasma depends on its relative rates of formation and destruction. Bradykinin is destroyed by two enzymes: a plasma carboxypeptidase (anaphylatoxin inactivator) removes the COOH-terminal arginine to yield an inactive octapeptide, and a dipeptidase (identical to the angiotensin-converting enzyme) removes the COOH-terminal Phe-Arg to yield a fragment of seven amino acids that is further fragmented to an end product of five amino acids. Formation of bradykinin is initiated on binding of Hageman factor (HF) to certain negatively charged surfaces on which it autoactivates by an autodigestion mechanism. Initiation appears to depend on a trace of intrinsic activity present in HF that is at most 1/4000 that of activated HF (HFa); alternatively traces of circulating HFa could subserve the same function. HFa then converts coagulation factor XI to activated factor XI (XIa) and prekallikrein to kallikrein. Kallikrein then digests high-molecular-weight kininogen (HMW-kininogen) to form bradykinin. Prekallikrein and factor XI circulate bound to HMW-kininogen and surface binding of these complexes is mediated via this kininogen. In the absence of HMW-kininogen, activation of prekallikrein and factor XI is much diminished; thus HMW-kininogen has a cofactor function in kinin formation and coagulation. Once a trace of kallikrein is generated, a positive feedback reaction occurs in which kallikrein rapidly activates HF. This is much faster than the HF autoactivation rate; thus most HFa is formed by a kallikrein-dependent mechanism. HMW-kininogen is also therefore a cofactor for HF activation, but its effect on HF activation is indirect because it occurs via kallikrein formation. HFa can be further digested by kallikrein to form an active fragment (HFf), which is not surface bound and acts in the fluid phase. The activity of HFf on factor XI is minimal, but it is a potent prekallikrein activator and can therefore perpetuate fluid phase bradykinin formation until it is inactivated by the C1 inhibitor. In the absence of C1 inhibitor (hereditary angioedema) HFf may also interact with C1 and activate it enzymatically. The resultant augmented bradykinin formation and complement activation may account for the pathogenesis of the swelling characteristic of hereditary angioedema and the serologic changes observed during acute attacks.
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PMID:Hageman factor-dependent pathways: mechanism of initiation and bradykinin formation. 655 44

There was no significant difference between the rates of protein degradation in cells of a leupeptin-producing strain and that of a leupeptin-nonproducing strain, the latter being derived from the former by mutation. Protein autodigestion in a cell homogenate of the leupeptin producer was sensitive to EDTA and chymotrypsin and less sensitive to leupeptin. On the contrary, protein degradation caused by exogenous trypsin in a similar homogenate was highly sensitive to leupeptin. A labeling experiment with [14C]-arginine of a culture of the leupeptin producer strain revealed that leupeptin was accumulated mostly in the medium and only slightly in the cells; the ratio between the amount in the medium and that in the cells was about 250:1. In contrast, leupeptin acid, the proximal intermediate having no antiplasmin activity, showed a ratio of 5:1.
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PMID:Biosynthesis of leupeptin. IV. Is protein turnover in leupeptin producer cells affected by leupeptin? 745 69

Hereditary pancreatitis (HP) is a rare, early-onset genetic disorder characterized by epigastric pain and often more serious complications. We now report that an Arg-His substitution at residue 117 of the cationic trypsinogen gene is associated with the HP phenotype. This mutation was observed in all HP affected individuals and obligate carriers from five kindreds, but not in individuals who married into the families nor in 140 unrelated individuals. X-ray crystal structure analysis, molecular modelling, and protein digest data indicate that the Arg 117 residue is a trypsin-sensitive site. Cleavage at this site is probably part of a fail-safe mechanism by which trypsin, which is activated within the pancreas, may be inactivated; loss of this cleavage site would permit autodigestion resulting in pancreatitis.
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PMID:Hereditary pancreatitis is caused by a mutation in the cationic trypsinogen gene. 884 Nov 72

Using an anti-(glutathione S-transferase-UVS.2 cDNA) Ig and uterine egg vitelline envelope (UEVE) protein of Xenopus laevis as probes, the hatching enzyme (HE) from Xenopus was solubilized in hatching medium and purified by gel-filtration and ion-exchange chromatography, and characterized in terms of its molecular mass and enzymatic properties. The hatching medium solubilized the UEVE and contained molecules reactive to the anti-(GST UVS.2) Ig against Xenopus HE. It was found that the HE had a molecular mass of 60 kDa, and often preparations also contained a 40-kDa form. The 60-kDa HE had a high hydrolytic and UEVE-solubilizing activity, and its activities against Boc-Leu-Gly-Arg-7-amino-4-methylcoumarin (-NH-Mec) and UEVE were inhibited by anti-(GST UVS.2) Ig in a dose-dependent manner. The 60-kDa form was easily autodigested into a 40-kDa form. The 40-kDa molecule alone had no detectable UEVE-solubilizing activity, even it still had high hydrolytic activity. It probably represents the main protease domain of the 60-kDa form after loss of two CUB repeats during autodigestion or digestion. The autodigestion of the 60-kDa molecule into 40-kDa molecule is probably a congenital behavior for successfully dissolving the embryo envelope during the hatching process. The two molecules may play different roles at different stages of the hatching process, during which they co-ordinate with each other to achieve complete solubilization of the embryo envelope, similar to the high and low choriolytic enzymes in medaka (Oryzias latipes). Their hydrolytic activity against Boc-Leu-Gly-Arg-NH-Mec was optimal at pH of 7.4, and with an apparent Km value of 200 micromol.L-1 at 30 degrees C. The HE is very sensitive to trypsin-specific inhibitors such as leupeptin, (4-amidino-phenyl)methane sulfonyl fluoride, diisopropyl fluorophosphate (DFP) and N-alpha-tosyl-L-lysylchloromethane (Tos-Lys-CH2Cl), indicates that it is a trypsin-type protease. The results on EDTA and some metal ions, combined with the occurrence of a astacin family metalloprotease-specific 'HExHxxGFxHE' sequence in the deduced HE amino-acid sequence, indicates that this HE is a Zn2+ metalloprotease.
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PMID:Properties of the hatching enzyme from Xenopus laevis. 1155 58

Hereditary pancreatitis is due to heterozygosity for gain-of-function mutations in the cationic trypsinogen gene which result in increased levels of active trypsin within pancreatic acinar cells and autodigestion of the pancreas. The number of disease-causing defects is generally considered to be low. To gain further insight into the molecular basis of this disorder, DNA sequence analysis of all five exons was performed in 109 unrelated patients with idiopathic chronic pancreatitis in order to determine the variability of the underlying mutations. Two German females and one German male were carriers of the most common N29I and R122H mutations (trypsinogen numbering system). In a Turkish proband, an arginine (CGT) to cysteine (TGT) substitution at amino acid position 116 was identified. Family screening demonstrated that the patient had inherited the mutation from his asymptomatic father and that he had transmitted it to both of his children, his daughter being symptomatic since the age of 3 years. In addition, a German male was found to be a heterozygote for a D100H (GAC-->CAC) amino acid replacement. Our data provide evidence for genetic heterogeneity of hereditary pancreatitis. The growing number of cationic trypsinogen mutations is expected to change current mutation screening practices for this disease.
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PMID:R116C mutation of cationic trypsinogen in a Turkish family with recurrent pancreatitis illustrates genetic microheterogeneity of hereditary pancreatitis. 1184 79

Today proteases have become an integral part of the food and feed industry, and plant latex could be a potential source of novel proteases with unique substrate specificities and biochemical properties. A new protease named "wrightin" is purified from the latex of the plant Wrightia tinctoria (Family Apocynaceae) by cation-exchange chromatography. The enzyme is a monomer having a molecular mass of 57.9 kDa (MALDI-TOF), an isoelectric point of 6.0, and an extinction coefficient (epsilon1%280) of 36.4. Optimum activity is achieved at a pH of 7.5-10 and a temperature of 70 degrees C. Wrightin hydrolyzes denatured natural substrates such as casein, azoalbumin, and hemoglobin with high specific activity; for example, the Km value is 50 microM for casein as substrate. Wrightin showed weak amidolytic activity toward L-Ala-Ala-p-nitroanilide but completely failed to hydrolyze N-alpha-benzoyl- DL-arginine-p-nitroanilide (BAPNA), a preferred substrate for trypsin-like enzymes. Complete inhibition of enzyme activity by serine protease inhibitors such as PMSF and DFP indicates that the enzyme belongs to the serine protease class. The enzyme was not inhibited by SBTI and resists autodigestion. Wrightin is remarkably thermostable, retaining complete activity at 70 degrees C after 60 min of incubation and 74% of activity after 30 min of incubation at 80 degrees. Besides, the enzyme is very stable over a broad range of pH from 5.0 to 11.5 and remains active in the presence of various denaturants, surfactants, organic solvents, and metal ions. Thus, wrightin might be a potential candidate for various applications in the food and biotechnological industries, especially in operations requiring high temperatures.
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PMID:A stable serine protease, wrightin, from the latex of the plant Wrightia tinctoria (Roxb.) R. Br.: purification and biochemical properties. 1822 Mar 46


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