Use of nitrogen-15 kinetic isotope effects to elucidate details of the chemical mechanism of human immunodeficiency virus 1 protease. NLM AIDSLINE Important note: Information in this article was accurate in 1994. The state of the art may have changed since the publication date.

Click here to return to AIDSLINE main menu
DonateNow
Print this Article


Use of nitrogen-15 kinetic isotope effects to elucidate details of the chemical mechanism of human immunodeficiency virus 1 protease.

Biochemistry. 1993 Nov 23;32(46):12380-5. Unique Identifier : AIDSLINE MED/94059947
Rodriguez EJ; Angeles TS; Meek TD; Department of Pharmaceutical Technologies, SmithKline Beecham; Pharmaceuticals, King of Prussia, Pennsylvania 19406.

Abstract: We have used 15N kinetic isotope effects of the HIV-1 protease-catalyzed peptidolysis of Ac-Ser-Gln-Asn-Tyr-Pro-Val-Val-NH2 to characterize the chemical mechanism of this enzyme. In addition, the multiple isotope effects have been determined by measuring the 15N kinetic isotope effects in both H2O and D2O. The isotope effects, measured on values of V/K, were determined by the incorporation of a radiolabel (tritium and 14C in peptides bearing the heavy and light isotopes, respectively) at a position remote from the isotopically labeled scissile peptide bond, such that the isotope effect was determined by measurement of the change in the 14C/3H ratio in recovered substrates at various fractions of reaction. At pH = 6.0 (37 degrees C), the nitrogen isotope effects were slightly, but significantly, inverse in both solvents: 15(V/K)H2O = 0.995 +/- 0.002, and 15(V/K)D2O = 0.992 +/- 0.003. The observation of an inverse nitrogen kinetic isotope effect implies that bonding to the nitrogen atom is becoming stiffened in a reaction transition state, and since this inverse isotope effect is enhanced in D2O, this isotope effect likely arises from protonation of the proline nitrogen atom.(ABSTRACT TRUNCATED AT 250 WORDS)
Keywords: Amino Acid Sequence HIV Protease/*METABOLISM HIV-1/*ENZYMOLOGY Kinetics Molecular Sequence Data Nitrogen Isotopes Oligopeptides/METABOLISM Recombinant Proteins Structure-Activity Relationship JOURNAL ARTICLEKWDaminoacidsequencehivprotease/KWDmetabolismhiv-1/KWDenzymologykineticsmolecularsequencedatanitrogenisotopesoligopeptides/metabolismrecombinantproteinsstructure-activityrelationshipjournalarticle
940330
M9430968

Copyright © 1994 - National Library of Medicine. Reproduced under license with the National Library of Medicine, Bethesda, MD.

AEGiS is a 501(c)3, not-for-profit, tax-exempt, educational corporation. AEGiS is made possible through unrestricted funding from Boehringer Ingelheim, Bridgestone/Firestone Charitable Trust, Bristol-Myers Squibb Company, Elton John AIDS Foundation, Gill Foundation, the National Library of Medicine, Quest Diagnostics, Roche and Trimeris, and donations from users like you. Always watch for outdated information. This article first appeared in 1994. This material is designed to support, not replace, the relationship that exists between you and your doctor.

AEGiS presents published material, reprinted with permission and neither endorses nor opposes any material. All information contained on this website, including information relating to health conditions, products, and treatments, is for informational purposes only. It is often presented in summary or aggregate form. It is not meant to be a substitute for the advice provided by your own physician or other medical professionals. Always discuss treatment options with a doctor who specializes in treating HIV.

Copyright ©1980, 1994. AEGiS. All materials appearing on AEGiS are protected by copyright as a collective work or compilation under U.S. copyright and other laws and are the property of AEGiS, or the party credited as the provider of the content. .