title: Thermal inactivation of a heat-resistant lipase produced by the psychotrophic bacterium Pseudomonas fluorescens.
abstract: Lipase from Pseudomonas fluorescens was studied for thermostability at temperatures ranging from 100 C to 160 C. The heat treatments were in two media, and heating times necessary to inactivate 90% of the enzyme at constant temperature were extremely long even at high temperatures, e.g. 3.6 min at 140 C in nutrient broth and 2.0 min at 170 C in skim milk. The increments of temperature to reduce these heating times 90% were 37.0 C in nutrient broth and 38.9 C in skim milk. The lipase was inactivated only partly after 20 h at 20 C in 8 M urea, 6 M guanidine hydrochloride, and 1.0% sodium dodecyl sulfate. Four percent 2-mercaptoethanol showed no effect.
mesh_terms: D000818:Animals; D002474:Cell-Free System; D004355:Drug Stability; D006146:Guanidines / Q000494:pharmacology; D006358:Hot Temperature; D008049:Lipase / Q000037:antagonists & inhibitors*; D008892:Milk / Q000201:enzymology; D011489:Protein Denaturation; D011551:Pseudomonas fluorescens / Q000201:enzymology*; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology; D013997:Time Factors; D014508:Urea / Q000494:pharmacology
chemical_list: D006146:Guanidines; D012967:Sodium Dodecyl Sulfate; D014508:Urea; D008049:Lipase