Inhibition by gossypol of cyclic nucleotide-independent phosvitin kinase from pig testis.
Gossypol, a male anti-fertility agent, was found to be an inhibitor of cyclic nucleotide-independent phosvitin kinase from pig testis. The IC50 value (concentration causing 50% inhibition) was 42 microM using phosvitin as substrate. Kinetic analysis indicated that the compound inhibited the enzyme noncompetitively with respect to ATP (Ki = 17 microM) and competitively with respect to phosvitin (Ki = 11 microM). The gossypol inhibition was reversed by the addition of polyamines. The compound also inhibited phosphorylation of high mobility group (HMG) proteins HMG 14 and 17 (the endogenous substrates in the testis located in nucleosome), with an IC50 value of 48 microM.
Katoh
N
N
Kimura
K
K
D000818:Animals; D006072:Gossypol / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D047428:Protein Kinase Inhibitors; D013552:Swine / Q000378:metabolism*; D013737:Testis / Q000187:drug effects / Q000201:enzymology*
D047428:Protein Kinase Inhibitors; D006072:Gossypol