Naim H Y
Institut für Mikrobiologie, Heinrich-Heine-Universität Düsseldorf, Germany.
Biol Chem Hoppe Seyler. 1995 Apr;376(4):255-8.
The pro-region of intestinal lactase-phlorizin hydrolase (LPH alpha) has been proposed to be important for the correct folding of pro-LPH and mature LPH (LPH beta). In this communication, analysis of the catalytic function of the LPH alpha pro-region is presented. Expression of a cDNA encoding LPH alpha in COS-1 cells reveals a polypeptide that does not hydrolyse lactose. Likewise, no lactase activity is detected in LPH alpha purified from trypsin-treated pro-LPH. Mixing of LPH alpha and LPH beta does not lead to the activation of the latter. We conclude that LPH alpha does not contribute to the lactase activity despite the strong homologies with mature LPH beta. LPH alpha may play an important role as an intra-molecular chaperone.
肠乳糖酶-根皮苷水解酶（LPHα）的前区域被认为对前体LPH和成熟LPH（LPHβ）的正确折叠很重要。在本通讯中，对LPHα前区域的催化功能进行了分析。在COS-1细胞中表达编码LPHα的cDNA，发现一种不水解乳糖的多肽。同样，从经胰蛋白酶处理的前体LPH中纯化得到的LPHα也未检测到乳糖酶活性。LPHα和LPHβ混合不会导致后者的激活。我们得出结论，尽管LPHα与成熟的LPHβ有很强的同源性，但它对乳糖酶活性没有贡献。LPHα可能作为分子内伴侣发挥重要作用。
