Ellmers B R, Rhinehart B L, Robinson K M
Biochem Pharmacol. 1987 Jul 15;36(14):2381-5. doi: 10.1016/0006-2952(87)90607-1.
Castanospermine is a potent inhibitor of rat hepatic lysosomal alpha-glucosidase in vitro. The alkaloid showed time-dependent inhibition with an IC50 of 5 X 10(-6) M without preincubation and 1 X 10(-7) M with 1 hr of preincubation. Inhibition appeared competitive without preincubation but noncompetitive after preincubation. The time-dependent inactivation of the enzyme followed pseudo-first-order kinetics with an inactivation constant of 1.2 X 10(3) M-1 sec-1. The apparent irreversibility of enzyme inhibition by castanospermine is postulated to be by tight-binding inhibition.
栗精胺在体外是大鼠肝脏溶酶体α-葡萄糖苷酶的强效抑制剂。该生物碱表现出时间依赖性抑制，未预孵育时IC50为5×10⁻⁶ M，预孵育1小时后为1×10⁻⁷ M。未预孵育时抑制表现为竞争性，但预孵育后为非竞争性。酶的时间依赖性失活遵循假一级动力学，失活常数为1.2×10³ M⁻¹ s⁻¹。推测栗精胺对酶抑制的明显不可逆性是通过紧密结合抑制实现的。
