These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Substrate effects on the enzymatic activity of alpha-chymotrypsin in reverse micelles.
    Author: Mao Q, Walde P.
    Journal: Biochem Biophys Res Commun; 1991 Aug 15; 178(3):1105-12. PubMed ID: 1872834.
    Abstract:
    Six different substrates have been used for measuring the activity of alpha-chymotrypsin in reverse micelles formed by sodium bis(2-ethylhexyl) sulfosuccinate (AOT) in isooctane. The substrates were glutaryl-Phe p-nitroanilide, succinyl-Phe p-nitroanilide, acetyl-Phe p-nitroanilide, succinyl-Ala-Ala-Phe p-nitroanilide, succinyl-Ala-Ala-Pro-Phe p-nitroanilide and acetyl-Trp methyl ester. It has been shown that the dependence of the kinetic constants (kcat and Km) on the water content of the system, on wo (= [H2O]/[AOT]), is different for the different substrates. This indicates that activity-wo profiles for alpha-chymotrypsin in reverse micelles not only reflect an intrinsic feature of the enzyme alone. For the p-nitroanilides it was found that the lower kcat (and the higher Km) in aqueous solution, the higher kcat as well as Km in reverse micelles. "Superactivity" of alpha-chymotrypsin could only be found with the ester substrate and with relatively "poor" p-nitroanilides. The presence of a negative charge in the substrate molecule is not a prerequisite for alpha-chymotrypsin to show "superactivity".
    [Abstract] [Full Text] [Related] [New Search]