Yüksel K U, Gracy R W
Arch Biochem Biophys. 1986 Aug 1;248(2):452-9. doi: 10.1016/0003-9861(86)90498-4.
The effects of pH, temperature, buffer ion, ionic strength, protein concentration, and substrate on the rates of specific, spontaneous deamidations of Asn-15 and Asn-71 of human triosephosphate isomerase were examined. Elevated temperature and pH facilitate the deamidations, and the deamidation rate is dependent on the specific buffer ions indicating a general base catalysis mechanism. The presence of substrate also enhances the rates of deamidation. The effect of substrate may be related to conformational changes in the catalytic center which are known to cause changes in the subunit-subunit contact sites where Asn-15 and Asn-71 are located. The enhanced deamidation in the presence of substrate may, in part, account for the more rapid rate of deamidation observed in vivo.
研究了pH值、温度、缓冲离子、离子强度、蛋白质浓度和底物对人磷酸丙糖异构酶Asn-15和Asn-71特定自发脱酰胺速率的影响。升高温度和pH值会促进脱酰胺反应，且脱酰胺速率取决于特定的缓冲离子，这表明存在一般碱催化机制。底物的存在也会提高脱酰胺速率。底物的作用可能与催化中心的构象变化有关，已知这种变化会导致Asn-15和Asn-71所在的亚基-亚基接触位点发生改变。底物存在时脱酰胺作用增强，这可能部分解释了在体内观察到的更快的脱酰胺速率。
