Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.64 (proteinase K)
 4,071 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cytochrome c oxidase from rat liver was incubated with various proteinases of different specificities and the enzymic activity was measured after various incubation times. A loss of catalytic activity was found after digestion with proteinase K, aminopeptidase M and a mitochondrial proteinase from rat liver. In each case the decrease in enzymic activity was compared with the changes in intensities of the polypeptide pattern obtained after sodium dodecyl sulfate polyacrylamide gel electrophoresis. The susceptibilities of the subunit polypeptides of the soluble cytochrome c oxidase to proteinases were very different. Whereas subunit I was most susceptible, subunits V--VII were rather resistant to degradation. From the relative inaccessibility of subunits V--VII to proteinases it is likely that these polypeptides are buried in the interior of the enzyme complex.
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PMID:Catalytic activity and arrangement of subunit polypeptides in rat liver cytochrome c oxidase as studied by proteolysis. 624 69

Pronase, proteinase K, carboxypeptidases A and B, aminopeptidase M, intestinal mucosa exopeptidases and prolidase, immobilized to derivatized controlled-pore glass beads, were used in a study of total enzymic hydrolysis of proteins. The combined use of immobilized enzymatic and acid hydrolysis, for assessment of protein quality, will give a more accurate chemical score than that afforded by acid hydrolysis alone. Amino acid analysis of enzymic hydrolysates of native protein substrates (beta-lactoglobulin and insulin) yielded 92% of the theoretical values and 103% of the values observed for standard acid hydrolysates. These results suggest that using a combination of immobilized proteases in concert gives essentially total hydrolysis of protein substrates in a time period (18-24 h) comparable to conventional acid hydrolysis methods.
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PMID:Compositional analysis of proteins following hydrolysis by immobilized proteases. 644 Aug 87

An endogenous inhibitor of L-Dopa decarboxylase was identified and purified from human serum. In Triton X-114 partitioning experiments, the inhibitor was recovered in the detergent enriched phase, suggesting a hydrophobic nature. Purification was achieved by means of proteinase K digestion, ammonium sulphate precipitation, phenyl sepharose hydrophobic chromatography and subsequent extraction from a nondenaturing polyacrylamide gel. This purification scheme resulted in the isolation of a single 25 kDa band, bearing L-Dopa decarboxylase inhibitory activity. The purified molecule was found to be resistant to heat and digestion by various proteases. Proteolytic digestion of the purified inhibitor by pronase and aminopeptidase M was achieved only following carboxymethylation. The biological importance of the presence of an L-Dopa decarboxylase activity inhibitor in normal biological fluids remains to be elucidated. The better understanding of the regulation of Ddc enzymatic activity could prove valuable in the clarification of the enzyme's role in a series of pathological conditions, as well as, in physiological regulatory mechanisms.
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PMID:Purification of an endogenous inhibitor of L-Dopa decarboxylase activity from human serum. 1617 68