地中海实蝇酸性核糖核酸酶的纯化、分子及酶学特性分析

Purification, molecular and enzymic characterization of an acid RNase from the insect Ceratitis capitata.

作者信息

García-Segura J M, Orozco M M, Fominaya J M, Gavilanes J G

出版信息

Eur J Biochem. 1986 Jul 15;158(2):367-72. doi: 10.1111/j.1432-1033.1986.tb09760.x.

DOI:10.1111/j.1432-1033.1986.tb09760.x

Abstract

An acid ribonuclease has been purified from the insect Ceratitis capitata. The specific activity of the purified enzyme is 580 units/mg. This enzyme is a single polypeptide chain of about 35.5 kDa, containing only one disulfide bridge and no free -SH groups. The A0.1%1cm at 280 nm is 1.90. The hydrodynamic radius of the native enzyme is 2.5 nm. The secondary structure of this RNase is composed of 10% alpha-helix, 31% beta-structure and 59% aperiodic conformation with an average number of residues per helical segment of 10, based on circular dichroic measurements. Optimum parameters for the enzyme activity are pH 5.5, 0.15 M ionic strength and 40 degrees C. Divalent cations are not required for the enzymic catalysis. This enzyme has been characterized as cyclizing endoribonuclease.

摘要

已从地中海实蝇中纯化出一种酸性核糖核酸酶。纯化酶的比活性为580单位/毫克。该酶是一条约35.5 kDa的单多肽链，仅含有一个二硫键且无游离巯基。在280 nm处的A0.1%1cm为1.90。天然酶的流体动力学半径为2.5 nm。基于圆二色性测量，该核糖核酸酶的二级结构由10%的α-螺旋、31%的β-结构和59%的无规构象组成，每个螺旋片段的平均残基数为10。酶活性的最佳参数为pH 5.5、离子强度0.15 M和40℃。酶催化不需要二价阳离子。该酶已被鉴定为环化内切核糖核酸酶。