大鼠肝脏中一种被鉴定为鸟氨酸氨甲酰基转移酶的镉结合蛋白。

A cadmium-binding protein in rat liver identified as ornithine carbamoyltransferase.

作者信息

Aoki Y, Sunaga H, Suzuki K T

机构信息

National Institute for Environmental Studies, Ibaraki, Japan.

出版信息

Biochem J. 1988 Mar 15;250(3):735-42. doi: 10.1042/bj2500735.

DOI:10.1042/bj2500735

PMID:3390141

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC1148919/

Abstract

A cadmium-binding protein of Mr about 40,000 (40K Cd-BPa) was detected in rat liver by Western blotting [Aoki, Kunimoto, Shibata & Suzuki (1986) Anal. Biochem. 157, 117-122]. It was characterized and identified as ornithine carbamoyltransferase (OCTase, EC 2.1.3.3) on the basis of coincidence of their physicochemical and enzymological features. The amino acid sequence of the N-terminal and those of three tryptic digests in 40K Cd-BPa were identical with those of OCTase. The Mr values of the denatured and native forms of 40K Cd-BPa (39,000 and 110,000 respectively) were the same as those of OCTase. 40K Cd-BPa showed, as OCTase activity, a specific activity of 230 mumol/min per mg of protein and Km of 0.6 mM for ornithine, this value also being essentially the same as that for OCTase. A rabbit antibody against OCTase reacted with 40K Cd-BPa. The native form of 40K Cd-BPa bound to 0.8 molar equiv, of cadmium, with a dissociation constant of 7.6 x 10(-6) M.

摘要

通过蛋白质免疫印迹法在大鼠肝脏中检测到一种分子量约为40000的镉结合蛋白（40K Cd-BPa）[青木、国本、柴田和铃木（1986年）《分析生物化学》157卷，第117 - 122页]。基于其物理化学和酶学特征的一致性，对其进行了表征并鉴定为鸟氨酸氨甲酰基转移酶（OCTase，EC 2.1.3.3）。40K Cd-BPa的N端氨基酸序列以及三种胰蛋白酶消化产物的氨基酸序列与OCTase的相同。40K Cd-BPa变性形式和天然形式的分子量（分别为39000和110000）与OCTase的相同。40K Cd-BPa表现出与OCTase活性相同的比活性，即每毫克蛋白质230 μmol/分钟，对鸟氨酸的Km值为0.6 mM，该值也与OCTase的基本相同。一种针对OCTase的兔抗体与40K Cd-BPa发生反应。40K Cd-BPa的天然形式与0.8摩尔当量的镉结合，解离常数为7.6×10⁻⁶ M。