抄録
EA4, an ATPase purified from Bombyx diapause eggs, exhibits one-time transitory burst activation two weeks after chilling at 5°C. The time of sudden increase in the EA4 activity is thought to be equivalent to that observed in vivo and is coincident with the chilling period indispensable for diapause termination. EA4 is a glycoprotein, and the carbohydrate moiety is involved in the EA4 activation through the interaction with peptides named PIN that corresponds to fragments of egg-specific protein. PINs inhibit the ATPase activity to delay the initiation of the activation and also inhibit deglycosylation of EA4 by PNGase F. The rate of inhibition increases as a function of increasing PIN amounts added. When 80nmol of PINs are added to 1nmol of EA4, the deglycosylation is almost completely inhibited as well as the ATPase activities. Those peptides of similar molecular weight to PINs, of hydrophobicity and others do not inhibit the deglycosylation. PINs may recognize the sugar chain of EA4 specifically and they also may bind the sugar directly or the site close to the sugar where PNGase F works, by which PINs regulate the initiation of EA4 activation.
