title: Identification of three high molecular mass cysteine proteinases from rat skeletal muscle.
abstract: Three cysteine proteinases were isolated from the post-myofibrillar fraction of rat skeletal muscle. Proteinase I preferentially hydrolyzes Z-Phe-Arg-NMec with pH optimum at 8-9. The enzyme activity is stabilized by ATP against thermal inactivation. Proteinase II and III were not resolved by anion-exchange chromatography, by affinity chromatography on Arginine-Sepharose or by gel filtration. Proteinase II, splitting Bz-Val-Gly-Arg-NMec optimally at pH 10-10.5, is inactivated by ATP, whereas Proteinase III, hydrolyzing Suc-Ala-Phe-NMec at pH 7-7.5 is not affected by the nucleotide. The molecular mass of proteinase I is about 750 000 and that of proteinase II and III is about 650 000, as determined by gel filtration.
mesh_terms: D000818:Animals; D003546:Cysteine Endopeptidases; D010450:Endopeptidases / Q000302:isolation & purification* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007527:Isoenzymes / Q000302:isolation & purification / Q000378:metabolism; D007700:Kinetics; D008297:Male; D008970:Molecular Weight; D009132:Muscles / Q000201:enzymology*; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D007527:Isoenzymes; D010450:Endopeptidases; D003546:Cysteine Endopeptidases