骆驼蓬碱与酵母转化酶的相互作用。

Harmaline interactions with yeast invertase.

作者信息

Gill R K, Kaur J, Mahmood S, Nagpaul J P, Mahmood A

机构信息

Department of Biochemistry, Panjab University, Chandigarh.

出版信息

Indian J Biochem Biophys. 1998 Apr;35(2):86-90.

PMID:9753866

Abstract

The effect of harmaline, a plant alkaloid has been studied on yeast invertase activity in the absence and presence of 50mM Na+ as a function of pH. Harmaline (1-3 mM) inhibited the invertase activity at pH 5.2, 6.8 and 8 both in the absence (44-92%) and (22-85%) of Na+ ions. Kinetic analysis revealed that harmaline is a non-competitive inhibitor of invertase, at pH 5.2 and 6.8 but at pH 8, it produced a mixed type of inhibition, Km increased by 450% and 175% and Vmax decreased by 82% and 63% in the absence and presence of 50mM Na ions respectively. The observed inhibition of invertase by harmaline was reversible in nature. These findings suggest that the presence of Na+ site is not a prerequisite for the inhibition of enzyme by harmaline.

摘要

研究了植物生物碱哈尔满碱在有无50mM Na⁺存在的情况下对酵母转化酶活性的影响，该影响是pH的函数。在pH 5.2、6.8和8时，无论有无Na⁺离子（分别为44 - 92%和22 - 85%），哈尔满碱（1 - 3 mM）均抑制转化酶活性。动力学分析表明，在pH 5.2和6.8时，哈尔满碱是转化酶的非竞争性抑制剂，但在pH 8时，它产生混合型抑制，在无50mM Na⁺离子和有50mM Na⁺离子存在时，Km分别增加450%和175%，Vmax分别降低82%和63%。观察到哈尔满碱对转化酶的抑制本质上是可逆的。这些发现表明，Na⁺位点的存在不是哈尔满碱抑制该酶的必要条件。