Purification of a protein cofactor required for ADP-ribosylation of the stimulatory regulatory component of adenylate cyclase by cholera toxin

R. A. Kahn, A. G. Gilman

Research output: Contribution to journalArticlepeer-review

256 Scopus citations

Abstract

A factor (ARF) that is required for the cholera toxin-dependent ADP-ribosylation of the stimulatory, GTP-binding regulatory component (G(s)) of adenylate cyclase has been purified about 2000-fold from cholate extracts of rabbit liver membranes. ARS is an intrinsic membrane protein with M(r) = 21,000. The final product can be resolved into two polypeptides with very similar molecular weights; each of these has ARF activity. The ADP-ribosylation of G(s) can now be studied with defined components. GTP and ARF are both necessary cofactors. The data imply that the substrates for the activated toxin are NAD and a GTP·G(s)·ARF complex, and the reaction proceeds in a lipid environment. The apparent ability of ARF to bind to the α subunit of G(s) suggests that it may play another, unknown role in the regulation of adenylate cyclase activity.

Original languageEnglish (US)
Pages (from-to)6228-6234
Number of pages7
JournalJournal of Biological Chemistry
Volume259
Issue number10
StatePublished - 1984

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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