title: Preparation and characterization of proteases from Thermoactinomyces vulgaris. V. Investigations on autolysis and thermostability of the purified protease.
abstract: Thermitase, the main component of the proteases of the culture medium from Thermoactinomyces vulgaris, is degraded by autolyses (increase of liberated amino groups) and thereby inactivated especially at elevated temperature, at alkaline pH-values and in the absence of added substrates. As shown by polyacrylamide gel electrophoresis autolysis is an essential part during heat inactivation (complete disappearance of the thermitase band after heating the enzyme at 85 degrees C for 5 min). The quantitative comparison of autolysis and heat inactivation as well as the kinetics of reversible inhibition of the enzyme by HgCl2 at different temperatures showed that above 60 degrees C thermal denaturation of the enzyme protein contributes to thermitase inactivation. Ca2+-ions (20 mM) have a stabilizing effect against both autolysis and thermal denaturation (inactivation) of thermitase.
mesh_terms: D002118:Calcium / Q000494:pharmacology; D010450:Endopeptidases / Q000378:metabolism*; D006358:Hot Temperature; D008627:Mercuric Chloride; D008628:Mercury / Q000494:pharmacology; D008848:Micromonosporaceae / Q000201:enzymology*; D011480:Protease Inhibitors; D011489:Protein Denaturation; D012697:Serine Endopeptidases
chemical_list: D011480:Protease Inhibitors; D008627:Mercuric Chloride; D010450:Endopeptidases; D012697:Serine Endopeptidases; C022728:thermitase; D008628:Mercury; D002118:Calcium