H-THR-THR-TYR-ALA-ASP-PHE-ILE-ALA-SER-GLY-ARG-THR-GLY-ARG-ARG-ASN-ALA-ILE-NH2

PKI(5-22)amide is the active inhibitory fragment of the inhibitor of the cyclic AMP-dependent protein kinase (PKA). PKI(5-22)amide inhibits PKA activation, but fails to attenuate homologous desensitization of CRF1 receptors[1][2].

[1] Dautzenberg FM, et al. GRK3 mediates desensitization of CRF1 receptors: a potential mechanism regulating stress adaptation. Am J Physiol Regul Integr Comp Physiol. 2001 Apr;280(4):R935-46. DOI:10.1152/ajpregu.2001.280.4.R935
[2] Reed J, et al. Conformational analysis of PKI(5-22)amide, the active inhibitory fragment of the inhibitor protein of the cyclic AMP-dependent protein kinase. Biochem J. 1989 Dec 1;264(2):371-80. DOI:10.1042/bj2640371