ACYLATION OF ADENYLYL-CYCLASE CATALYST IS IMPORTANT FOR ENZYMATIC-ACTIVITY

Incubation of human thrombocytes in the presence of [H-3]palmitic acid leads to incorporation of this fatty acid into the cu subunit of G(s) as described [Linder et al., Proc. Natl, Acad. Sci. USA 90 (1993) 367 5-3679; Degtyarev et al., Biochemistry 32 (1993) 8057-8061] but also i nto the catalyst of adenylyl cyclase which has not been recognized bef ore. Treatment of labeled membranes with hydroxylamine released the la bel from both components. Label incorporated into the catalyst could b e identified as [H-3]palmitate. At the same time chemical deacylation caused partial loss of adenylyl cyclase activity.