The Enzymology of Phosphorylase Phosphatase (Protein Phosphatase-1)-A Personal Perspective

磷酸解酶磷酸酶（蛋白質磷酸酶－1）之酶學－個人之回顧

Ernest Y.C. Lee

《Zoological Studies》 34卷3期 (1995/07) Pp. 149-163

摘要

本文回顧過去二十年來我們實驗室在肝醣磷酸解酶磷酸酶（glycogen phosphorylase phosphatase）（蛋白質磷酸酶－1）之研究結果。此酶之酶學非常複雜，有關其特性之研究，著實花了一番功夫。在此實驗過程中，最主要的發現為純化其催化亞單元（catalytic subunit），及發現其抑制蛋白質（inhibitory proteins），其中抑制蛋白質-2與催化直單元可形成一複合體。後來又陸續發現許多不同型式之全酶存在，包括不同之催化單元與不同之調控單元（regulatory subunits）之結合。近年來，利用基因選殖技術證明催化單元是一保留性很高之蛋白質，並且在細胞有絲分裂時扮演著重要角色。利用大腸桿菌基因表現系統，已開啟研究此酶之構造－功能關係之門，此酶與其抑制性毒素之結合部位亦已經基因突變法確定出來。

關鍵字

蛋白質磷酸酶 ； 代謝作用之調控 ； 基因突變法

並列摘要

In this paper we review studies of phosphorylase phosphatase (protein phosphatase-1) that have been the focus of our work for the past two decades. The enzymology of the enzyme is complex, and the description of its properties has taken a great deal of effort. Key discoveries in this process were the isolation of the catalytic subunit of the enzyme, and the discovery of inhibitory proteins, one of which (inhibitor-2) forms a complex with the catalytic subunit. Later it was discovered that a number of holoenzyme forms existed, and that these consisted of complexes of the catalytic subunit with different regulatory subunits. In recent years, the cloning of the cDNAs for the catalytic subunit has demon-strated that it is a very highly conserved protein and that it plays a critical role in mitosis. Expression of the catalytic subunit in E. coli has opened the way for structure-function studies. The region involved in the binding of toxins which inhibit the enzyme have been identified by mutagenesis.

並列關鍵字

Protein phosphatase ； Metabolic control ； Mutagenesis