兔肝脏溶酶体中烟酰胺腺嘌呤二核苷酸核苷酶的证据。

Evidence for NAD nucleosidase in rabbit-liver lysosomes.

作者信息

Mellors A, Lun A K, Peled O N

出版信息

Can J Biochem. 1975 Feb;53(2):143-8. doi: 10.1139/o75-022.

Abstract

A method is described for the isolation of secondary lysosomes from homogenates of rabbit liver; The uptake of Triton WR-1339 by rabbit-liver lysosomes when administered by intraperitoneal injection was used to decrease the density of secondary lysosomes. Lysosomal fractions prepared by this method contain an NAD nucleosidase (NAD glycohydrolase, EC 3;2.25), an enzyme which has previously been considered to be associated with other subcellular fractions. The enzyme has maximum activity at pH 6 and cleaves both NAD and NADP. It is inhibited by nicotinamide (Ki equals 4.5 mM) and by HgCl2. Both nucleosidase and 2'-nucleotidase show in-vitro latency typical of lysosomal acid hydrolases. Rabbit-liver plasma-membrane fractions were isolated which contained most 5'-nucleotidase but relatively little nucleosidase, whereas rabbit liver lysosomes contain both 5'-nucleotidase and nucleosidase enzymes but little adenyl cyclase.

摘要

本文描述了一种从兔肝匀浆中分离次级溶酶体的方法；通过腹腔注射给予兔肝溶酶体 Triton WR-1339，利用其摄取来降低次级溶酶体的密度。用该方法制备的溶酶体组分含有一种 NAD 核苷酶（NAD 糖水解酶，EC 3;2.25），这种酶以前被认为与其他亚细胞组分相关。该酶在 pH 6 时具有最大活性，可切割 NAD 和 NADP。它受到烟酰胺（Ki 等于 4.5 mM）和 HgCl2 的抑制。核苷酶和 2'-核苷酸酶均表现出溶酶体酸性水解酶典型的体外潜伏性。分离出的兔肝血浆膜组分含有大部分 5'-核苷酸酶，但核苷酶相对较少，而兔肝溶酶体同时含有 5'-核苷酸酶和核苷酶，但腺苷酸环化酶很少。