2004 Volume 57 Issue 7 Pages 456-461
FR225659 was originally isolated as a novel gluconeogenesis inhibitor produced by fungal strain Helicomyces sp. No. 19353. To identify the target protein of FR225659, we synthesized high-performance affinity latex beads that immobilized FR225659 derivative FR253761 or FR259383. Using these beads, we identified FR225659 binding proteins as serine/threonine protein phosphatase type 1 (PP1) and type2A (PP2A) from rat hepatocyte crude extract. FR225659 and its synthetic derivatives were strongly inhibited the enzyme activities of purified catalytic subunits of PP1 and PP2A in vitro.