Dijkstra B W, Drenth J, Kalk K H
Nature. 1981 Feb 12;289(5798):604-6. doi: 10.1038/289604a0.
The esterolytic enzyme phospholipase A2 specificially splits the 2-acyl linkage of phosphoglycerides in a calcium-dependent reaction. In the pancreas the enzyme occurs as a zymogen which is activated on secretion into the duodenal tract by the removal of seven amino acid residues from the N terminus by trypsin. Having refined our X-ray analysis of the crystal structure of bovine pancreatic phospholipase A2 from 2.4 A (ref. 4) to 1.7 A resolution, we now describe how the structure of the molecule may account for the specificity of the enzyme and for the sudden and dramatic change in activity when the substrate concentration passes the critical micelle concentration.
酯解酶磷脂酶A2在钙依赖反应中特异性地裂解磷酸甘油酯的2-酰基键。在胰腺中，该酶以酶原形式存在，分泌到十二指肠后，被胰蛋白酶从N端去除七个氨基酸残基而激活。我们已将牛胰磷脂酶A2晶体结构的X射线分析从2.4埃（参考文献4）精修至1.7埃分辨率，现在我们描述该分子的结构如何解释酶的特异性以及当底物浓度超过临界胶束浓度时活性的突然显著变化。
