Accorsi A, Piatti E, Piacentini M P, Gini S, Fazi A
Istituto di Chimica Biologica, Universita' degli Studi di Urbino, Italy.
Prep Biochem. 1989;19(3):251-71. doi: 10.1080/10826068908544915.
A procedure has been developed for the purification of phosphoglucomutase from human red cell (phenotype PGM1 a1 or a3) lysates. It yields homogeneous isoenzyme preparations of the products ("primary" and "secondary") of the two PGM1 and PGM2 loci with distinctive pI (from 6.07 to 5.29). There are substantial differences between PGM1 and PGM2 isoenzymes, having single polypeptide chains of 58,500 and 69,000 Mr respectively and showing different thermostability. The kinetic properties of all the isoenzymes for the phosphoglucomutase reaction are essentially the same (apart from the specific activity of 1089-1263 units/mg for PGM1 forms vs 37-42 units/mg for PGM2 forms), but there are striking differences in substrate specificity. In fact the products of PGM1 locus are "true" phosphoglucomutases, being specific to mutate glucose monophosphates, whereas the PGM2 forms also display phosphoribomutase and glucose 1,6-bisphosphate synthetic activities. Some kinetic properties of these "side activities" are also reported.
已开发出一种从人红细胞（PGM1 a1或a3表型）裂解物中纯化磷酸葡萄糖变位酶的方法。该方法可得到两种PGM1和PGM2基因座产物（“一级”和“二级”）的均一同工酶制剂，其具有独特的等电点（从6.07至5.29）。PGM1和PGM2同工酶之间存在显著差异，它们分别具有58,500和69,000 Mr的单条多肽链，并且表现出不同的热稳定性。所有同工酶对于磷酸葡萄糖变位酶反应的动力学性质基本相同（PGM1形式的比活性为1089 - 1263单位/毫克，而PGM2形式的为37 - 42单位/毫克除外），但在底物特异性方面存在显著差异。实际上，PGM1基因座的产物是“真正的”磷酸葡萄糖变位酶，特异性地催化葡萄糖单磷酸的转化，而PGM2形式还表现出磷酸核糖变位酶和葡萄糖1,6 - 二磷酸合成活性。还报道了这些“副活性”的一些动力学性质。
