Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.27 (thermolysin)
 1,894 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Some proteases, i.e. trypsin, alpha-chymotrypsin, thermolysin, proteinase K, alpha-amylase, collagenase, and papain were investigated on their effect on isolated zonular fibers. All these enzymes but collagenase were zonulolytic active. An attack on the ground substance of the fibers by substances solving glycosaminoglycans and proteoglycans (hyaluronidase, EDTA, guanidinium chloride, H2O2) showed an increased effect of the enzymes used. These results suggest that the interfibrillar matrix has a protective function on the zonular fibers.
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PMID:[The attack of different proteases on isolated zonular fibers (author's transl)]. 13 75

Rat liver Cu,Zn-[35S]thionein and yeast Cu-thionein were subjected to proteolysis in vitro using equilibrium dialysis. The partially copper-loaded vertebrate thionein (2-7 Cu/mol) was affected by different proteases including thermolysin, proteinase K, protease from Streptomyces griseus and lysosomal enzymes. Unlike the 2Cu-thionein the respective 7Cu-thiolate-centred metallothionein was hardly proteolytically digested. In contrast to fully copper-loaded native yeast Cu-thionein both the H2O2-oxidized and the metal-free protein were effectively cleaved in the presence of proteinase K. It is important to realize that the native Cu(I)-thiolate chromophore survives the proteolytic attack. When the copper-sulphur bonding is broken and the same amount of copper is unspecifically bound to the thionein portion, proteolysis proceeds identically with respect to the rate observed in the presence of the apoprotein. The unsuccessful proteolysis of native Cu-thionein is not attributable to a simple copper-dependent inhibition of the proteinases. It is suggested that prior to proteolysis the copper-sulphur clusters must be destroyed.
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PMID:The role of Cu(I)-thiolate clusters during the proteolysis of Cu-thionein. 308 72

Rat liver 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase catalyzes exchange reactions between ADP and ATP and between fructose-6-P and fructose-2,6-P2 at histidyl residues. Limited proteolysis of the enzyme with thermolysin yielded an enzyme core with a subunit molecular weight of 35,000-38,000. This enzyme core had no kinase activity and a 2-fold activated bisphosphatase activity whose sensitivity to the product inhibitor fructose-6-P was unchanged. The thermolysin-treated enzyme also did not catalyze the fructose-6-P/fructose-2,6-P2 exchange reaction but did catalyze the ADP/ATP exchange. These results suggest that 1) the enzyme's reactions may be catalyzed at two active sites, 2) there are at least two fructose-6-P binding sites, 3) the fructose-6-P/fructose-2,6-P2 exchange is catalyzed only at the kinase site, and 4) inactivation of the exchange and kinase reactions by thermolysin digestion is due to the loss of the fructose-6-P binding site of the kinase. Also consistent with these conclusions was the finding that oxidation of the enzyme with ascorbate/Fe3+ or H2O2 resulted in complete loss of the kinase activity as well as the fructose-6-P/fructose-2,6-P2 exchange but did not affect the bisphosphatase activity or the ADP/ATP exchange. Dithiothreitol could completely reactivate the ascorbate/Fe3+-inactivated enzyme, suggesting that oxidation occurred at a sulfhydryl group(s) essential for fructose-6-P binding in the kinase reaction. In addition, the kinase and fructose-6-P/fructose-2,6-P2 exchange reactions were more sensitive to inactivation by diethylpyrocarbonate than was the bisphosphatase. The different responses of the kinase and bisphosphatase reactions to the action of these various protein-modifying agents and to thermolysin digestion support the existence of a separate site for each reaction and an essential role for sulfhydryl groups at the sugar-phosphate-binding site(s) of the kinase.
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PMID:Differential effects of proteolysis and protein modification on the activities of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase. 609 63

The stability of glutathione peroxidase was assessed in vitro via oxidative inactivation by peroxides and a peroxidizing fatty acid and by renaturation and proteolysis. The stability of glutathione peroxidase to methyl ethyl ketone peroxide, H2O2, linoleic acid hydroperoxide, and peroxidizing methyl linolenate was compared with the stability of several other enzymes. Sulfhydryl enzymes were the most labile to all four treatments. Some of the enzymes tested were very stable to methyl ethyl ketone peroxide but very labile to linoleic acid hydroperoxide treatment. Glutathione peroxidase in the absence of glutathione was relatively slowly inactivated by each treatment. Linoleic acid hydroperoxide damage to glutathione peroxidase was characterized by release of a nonstoichiometric amount of selenite from the protein. Glutathione peroxidase samples lost all of their activity when (i) acidified to pH 2, (ii) heated 5 min at 100 degrees C, and (iii) treated with 6 M guanidinium hydrochloride or 8.5 M urea and heated 5 min at 100 degrees C. When the pH 2 sample was neutralized or the guanidinium hydrochloride-treated sample was diluted 101-fold, about 80% of the original activity was recovered in 30 min. The samples treated with urea and heat recovered no activity when diluted 101-fold. No loss of glutathione peroxidase occurred during treatment for 24 h within trypsin or thermolysin. Based on these results, glutathione peroxidase appears to be a relatively stable enzyme, and thus is is well-suited to perform its role in peroxide detoxification and prevention of oxidative deterioration of cells.
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PMID:Evidence for suitability of glutathione peroxidase as a protective enzyme: studies of oxidative damage, renaturation, and proteolysis. 630 80