三磷酸腺苷及其他核苷三磷酸对腺嘌呤磷酸核糖转移酶的刺激作用。

Stimulation of adenine phosphoribosyltransferase by adenosine triphosphate and other nucleoside triphosphates.

Murray A W, Wong P C

Biochem J. 1967 Aug;104(2):669-74. doi: 10.1042/bj1040669.

Abstract

Adenine phosphoribosyltransferase was protected from inactivation on heating at 55 degrees by the presence of 5-phosphoribosyl pyrophosphate. ATP, adenine, AMP or GMP had no protective effect on the activity of this enzyme. The presence of either 5-phosphoribosyl pyrophosphate or ATP did not protect adenine phosphoribosyltransferase against the loss of ATP stimulation obtained by heating at 55 degrees . 2. At pH5.3 and 6.0 adenine phosphoribosyltransferase was stimulated by a narrow range of ATP concentration (15-25mum). At pH6.5 and 7.0 maximum stimulation was obtained with 25-30mum-ATP, and at pH7.4, 8.2 and 8.85 maximum stimulation was obtained over a wide range of ATP concentrations (60-200mum). With extracts that had been heated for 30min. at 55 degrees no stimulation was observed at either pH5.3 or 7.4 with ATP concentrations up to 100mum. 3. Short periods of heating at 55 degrees (1, 2 or 5min.) increased the stimulation of adenine phosphoribosyltransferase obtained with various concentrations of ATP. 4. The addition of CTP, GTP, deoxy-GTP, deoxy-TTP or XTP to assay mixtures resulted in weak stimulation of adenine-phosphoribosyltransferase activity. 5. It is suggested that there are at least three different forms of adenine phosphoribosyltransferase, each with a different affinity for ATP.

摘要

在5-磷酸核糖焦磷酸存在的情况下，腺嘌呤磷酸核糖转移酶在55℃加热时可免受失活影响。ATP、腺嘌呤、AMP或GMP对该酶的活性没有保护作用。5-磷酸核糖焦磷酸或ATP的存在并不能保护腺嘌呤磷酸核糖转移酶免受55℃加热导致的ATP刺激作用丧失。2. 在pH5.3和6.0时，腺嘌呤磷酸核糖转移酶受到较窄范围的ATP浓度（15-25μM）刺激。在pH6.5和7.0时，25-30μM-ATP可获得最大刺激，而在pH7.4、8.2和8.85时，在较宽范围的ATP浓度（60-200μM）下可获得最大刺激。对于在55℃加热30分钟的提取物，在pH5.3或7.4时，ATP浓度高达100μM时均未观察到刺激作用。3. 在55℃短时间加热（1、2或5分钟）可增强不同浓度ATP对腺嘌呤磷酸核糖转移酶的刺激作用。4. 向测定混合物中添加CTP、GTP、脱氧GTP、脱氧TTP或XTP会导致腺嘌呤磷酸核糖转移酶活性受到微弱刺激。5. 有人提出，至少存在三种不同形式的腺嘌呤磷酸核糖转移酶，每种对ATP的亲和力不同。