Substrate binding is required for release of product from mammalian protein farnesyltransferase.

Published

Journal Article

Protein farnesyltransferase (FTase) catalyzes the modification by a farnesyl lipid of Ras and several other key proteins involved in cellular regulation. Previous studies on this important enzyme have indicated that product dissociation is the rate-limiting step in catalysis. A detailed examination of this has now been performed, and the results provide surprising insights into the mechanism of the enzyme. Examination of the binding of a farnesylated peptide product to free enzyme revealed a binding affinity of approximately 1 microM. However, analysis of the product release step under single turnover conditions led to the surprising observation that the peptide product did not dissociate from the enzyme unless additional substrate was provided. Once additional substrate was provided, the enzyme released the farnesylated peptide product with rates comparable with that of overall catalysis by FTase. Additionally, stable FTase-farnesylated product complexes were formed using Ras proteins as substrates, and these complexes also require additional substrate for product release. These data have major implications in both our understanding of overall mechanism of this enzyme and in design of inhibitors against this therapeutic target.

Full Text

Duke Authors

Cited Authors

  • Tschantz, WR; Furfine, ES; Casey, PJ

Published Date

  • April 11, 1997

Published In

Volume / Issue

  • 272 / 15

Start / End Page

  • 9989 - 9993

PubMed ID

  • 9092540

Pubmed Central ID

  • 9092540

International Standard Serial Number (ISSN)

  • 0021-9258

Digital Object Identifier (DOI)

  • 10.1074/jbc.272.15.9989

Language

  • eng

Conference Location

  • United States