Gagnon C, Harbour D, De Lamirande E, Bardin C W, Dacheux J L
Biol Reprod. 1984 May;30(4):953-8. doi: 10.1095/biolreprod30.4.953.
A more sensitive assay for protein methylesterase (PME) was developed. The new assay measures the methanol formed from hydrolysis of protein-methyl esters instead of methyl esters remaining on proteins. The formation of methanol is linear with time and enzyme concentration up to 20% of substrate hydrolysis. With this assay, we have detected very low PME activity in rat spermatozoa from cauda epididymidis. However, PME activity in spermatozoa from caput epididymidis was 10-fold higher. In a more detailed study on bull spermatozoa during epididymal maturation, we observed that PME activity was low in testicular spermatozoa, increased in spermatozoa from caput epididymidis to a maximum of 1.29 pmol/mg protein, and progressively decreased to a very low level (0.06 pmol/mg protein) in spermatozoa from cauda epididymidis. The drop in PME activity during epididymal transit parallels the progressive acquisition of motility and fertilizing capacity by spermatozoa.
开发了一种更灵敏的蛋白质甲酯酶（PME）检测方法。新方法测量的是蛋白质甲酯水解产生的甲醇，而不是残留在蛋白质上的甲酯。甲醇的生成与时间和酶浓度呈线性关系，直至底物水解达到20%。通过这种检测方法，我们在来自附睾尾的大鼠精子中检测到了非常低的PME活性。然而，来自附睾头的精子中的PME活性要高10倍。在对公牛精子附睾成熟过程的更详细研究中，我们观察到睾丸精子中的PME活性较低，从附睾头的精子开始增加，最高达到1.29 pmol/mg蛋白质，而在附睾尾的精子中逐渐降低到非常低的水平（0.06 pmol/mg蛋白质）。精子在附睾转运过程中PME活性的下降与精子运动能力和受精能力的逐步获得相平行。
