Inactivation of the catalytic subunit of bovine cAMP-dependent protein kinase by a peptide-based affinity inactivator |
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Authors: | S Mobashery M Doughty E T Kaiser |
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Institution: | Department of Chemistry, Wayne State University, Detroit, Michigan 48202. |
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Abstract: | A peptide affinity inactivator, Ac-Leu-Arg-Arg-Ala-(BrAc)Orn-Leu-Gly, was used as a tool to probe for active site residues in the catalytic subunit of bovine cAMP-dependent protein kinase. The peptide inactivated the catalytic subunit in an active site-directed and monophasic manner with a first-order rate constant of 0.03 min-1 and a dissociation constant of 675 microM. Studies with radioactive peptide indicated that approximately one equivalent of peptide was incorporated into each protein molecule. Protein sequencing identified the modified residue as Cys-199. A possible location for Cys-199 within the active site is suggested. |
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