title: Stability of protease Q against autolysis and in sodium dodecyl sulfate and urea solutions.
abstract: Protease Q, a recently discovered subtilisin-like protease, exhibited unusual stability in 10% sodium dodecyl sulfate (SDS) and 8 M urea solutions. In 2% SDS it exhibited higher activity than the control, and in 10% SDS it retained 50% of its original activity when azocoll was used as substrate. Kinetic studies showed that the decrease in the activity of protease Q in SDS solutions followed a first order kinetics with a half-life of 446, 278, 78, and 24 h in 1%, 2%, 5%, and 10% SDS, respectively, at 25 degrees C. Protease Q was also stable against autolysis. In 20 mM Tris-HCl buffer (pH 8.3) containing 1.0 mM CaCl2, protease Q had a half life of 2822 h and 725 h at room temperature and at 37 degrees C, respectively. The enzyme was able to completely hydrolyze beta-lactoglobulin, beta-casein, and keratin in 8-10 M urea.
authors.affiliation: Department of Food Science, University of Wisconsin-Madison 53706, USA.
authors.forename: X Q
authors.initials: XQ
authors.lastname: Han
authors.forename: S
authors.initials: S
authors.lastname: Damodaran
mesh_terms: D000595:Amino Acid Sequence; D001391:Azo Compounds / Q000378:metabolism; D001407:Bacillus / Q000201:enzymology*; D002364:Caseins / Q000378:metabolism; D003094:Collagen / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability; D007633:Keratins / Q000378:metabolism; D007700:Kinetics; D007782:Lactoglobulins / Q000378:metabolism; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000378:metabolism; D011489:Protein Denaturation; D012697:Serine Endopeptidases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology; D013379:Substrate Specificity; D013381:Subtilisins / Q000378:metabolism; D014508:Urea / Q000494:pharmacology
chemical_list: D001391:Azo Compounds; D002364:Caseins; D007782:Lactoglobulins; D009842:Oligopeptides; D012967:Sodium Dodecyl Sulfate; C028470:Azocoll; D007633:Keratins; C043307:succinyl-alanyl-alanyl-prolyl-phenylalanine-4-nitroanilide; D014508:Urea; D003094:Collagen; D012697:Serine Endopeptidases; D013381:Subtilisins; C109589:protease Q