Protein farnesyltransferase: kinetics of farnesyl pyrophosphate binding and product release.

Published

Journal Article

Protein farnesyltransferase (FTase) catalyzes the prenylation of Ras and several other key proteins involved in cell regulation. The mechanism of the FTase reaction was elucidated by pre-steady-state and steady-state kinetic analysis. FTase catalyzed the farnesylation of biotinylated peptide substrate (BiopepSH) by farnesyl pyrophosphate (FPP) to an S-farnesylated peptide (BiopepS-C15). The steady-state kinetic mechanism was ordered. FTase bound FPP in a two-step process with an effective dissociation rate constant of 0.013 s-1 and an overall Kd of 2.8 nM. BiopepSH reacted with FTase.FPP irreversibly, with a second-order rate constant of 2.2 x 10(5) M-1 s-1, to form FTase.BiopepS-C15. Because most of the FPP in FTase.FPP was trapped as FTase.BiopepS-C15 at high concentrations of BiopepSH, FPP dissociated slowly from the ternary complex relative to catalysis, so that the commitment to catalysis was high. The maximal rate constant for formation of FTase.BiopepS-C15 (enzyme-bound product) is much larger than kcat (0.06 s-1), indicating that product release is the rate-determining step in the reaction mechanism.

Full Text

Duke Authors

Cited Authors

  • Furfine, ES; Leban, JJ; Landavazo, A; Moomaw, JF; Casey, PJ

Published Date

  • May 23, 1995

Published In

Volume / Issue

  • 34 / 20

Start / End Page

  • 6857 - 6862

PubMed ID

  • 7756316

Pubmed Central ID

  • 7756316

International Standard Serial Number (ISSN)

  • 0006-2960

Digital Object Identifier (DOI)

  • 10.1021/bi00020a032

Language

  • eng

Conference Location

  • United States