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目的探讨纯化的人类胎盘碱性磷酸酶（ＰＬＡＰ）的部分性质，为其结构与功能的研究积累资料。②方法应用分光光度法观察了温度、酸碱度及抑制剂对酶活力的影响；同时对其紫外吸收光谱进行了测定。③结果在该实验条件下，酶的最适温度为６５℃，对热稳定，－２５℃冷冻后酶的活力明显下降；最适ｐＨ为１１．０，在ｐＨ７．０～１１．５之间稳定；以对硝基酚磷酸二钠为底物，其Ｋｍ值为０．２５ｍｍｏｌ／Ｌ；Ｌ－苯丙氨酸是ＰＬＡＰ的反竞争性抑制剂，其抑制常数为２．３５ｍｍｏｌ／Ｌ，而ＮａＨ２ＰＯ４是ＰＬＡＰ的竞争性抑制剂，其抑制常数为０．９９ｍｍｏｌ／Ｌ；酶蛋白的最大紫外吸收波长为２８０ｎｍ．④结论了解纯化ＰＬＡＰ的上述性质，有助于其结构与功能的研究。
Objective To investigate the partial properties of purified human placental alkaline phosphatase (PLAP) and to accumulate data on its structure and function. Methods The spectrophotometric method was used to observe the effects of temperature, pH, and inhibitor on the enzyme activity. The UV absorption spectra were also measured. The results under the experimental conditions, the enzyme optimum temperature of 65 ° C, the heat-stable, -25 ° C frozen enzyme activity decreased significantly; optimum pH of 11.0, at pH 7.0 ~ 11.5 Stable; with p-nitrophenol disodium phosphate as substrate, the Km value of 0.25mmol / L; L-phenylalanine PLAP anti-competitive inhibitor, the inhibition constant of 2.35mmol / L, and NaH2PO4 is a competitive inhibitor of PLAP with an inhibition constant of 0.99 mmol / L; the maximum UV absorption wavelength of the enzyme protein is 280 nm. ④ Conclusion Understanding the above properties of purified PLAP contribute to its structure and function of the study.