T. Hamaguchi et al., RK-682, A POTENT INHIBITOR OF TYROSINE PHOSPHATASE, ARRESTED THE MAMMALIAN-CELL CYCLE PROGRESSION AT G(1)PHASE, FEBS letters, 372(1), 1995, pp. 54-58
A specific inhibitor of protein tyrosine phosphatase (PTPase), RK-682
(3-hexadecanoyl-5-hydrosymethyl-tetronic acid) was isolated from micro
bial metabolites, In vitro, RK-682 inhibited dephosphorylation activit
y of CD45 and VHR with IC50 54 and 2.0 mu M, respectively, In situ, so
dium orthovanadate and RK-682 enhanced the phosphotyrosine level of Ba
ll-1 cells, a human B cell leukemia, but not the phosphoserine/threoni
ne level. The PTPase inhibitors, however, had the different arrest poi
nt on the cell cycle progression, Sodium orthovanadate inhibited the c
ell cycle progression at G(2)/M boundary phase, on the other hand, RK-
682 inhibited the G(1)/S transition.