Min K H, Sasaki S, Kashiwabara Y, Nisizawa K
J Biochem. 1977 Mar;81(3):547-53. doi: 10.1093/oxfordjournals.jbchem.a131489.
Two endo-alginate lyases [EC 4.2.2.3] differing in their mode of degradation of substrates and practically free of polymannuronide lyase activity were partially purified from Pseudomonas sp. cells. Their substrate specificities were investigated for two different kinds of alginate fragments; a polyguluronide (SG) and a polyuronide consisting of mannuronic (M) and guluronic (G) acid residues (SMG). The effects of various salts and some organic compounds such as EDTA and p-chloromercuribenzoate on the degradation of the two substrates were similar. High concentrations of the substrates similarly inhibited the action ofthe lyases, giving a bell-shaped plot. A polymannuronide alginate fragment (SM) which was a substrate for polymannuronide lyase but was not attacked by these guluronide lyases also inhibited the degradation of SG and SMG. The overall degradation velocities of a mixture of SG and SMG by both lyases coincided with those calculated from the Michaelis-Menten formula. Based on the above results, it was concluded that SG and SMG are attacked by the same endo-polyguluronide lyase.
从假单胞菌属（Pseudomonas sp.）细胞中部分纯化出两种内切海藻酸裂解酶[EC 4.2.2.3]，它们对底物的降解方式不同，且几乎没有聚甘露糖醛酸酶活性。研究了它们对两种不同类型海藻酸片段的底物特异性，一种是聚古罗糖醛酸（SG），另一种是由甘露糖醛酸（M）和古罗糖醛酸（G）残基组成的聚糖醛酸（SMG）。各种盐以及一些有机化合物如EDTA和对氯汞苯甲酸对这两种底物降解的影响相似。高浓度的底物同样抑制裂解酶的作用，呈现钟形曲线。一种聚甘露糖醛酸海藻酸片段（SM），它是聚甘露糖醛酸酶的底物，但不会被这些古罗糖醛酸酶攻击，也抑制了SG和SMG的降解。两种裂解酶对SG和SMG混合物的总体降解速度与根据米氏方程计算出的速度一致。基于上述结果，得出结论：SG和SMG受到同一种内切聚古罗糖醛酸裂解酶的作用。
