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 language | English (US) |
---|---|
Pages (from-to) | 6228-6234 |
Number of pages | 7 |
Journal | Journal of Biological Chemistry |
Volume | 259 |
Issue number | 10 |
State | Published - 1984 |
ASJC Scopus subject areas
- Biochemistry
- Molecular Biology
- Cell Biology