Tominaga Y, Tsujisaka Y
Biochim Biophys Acta. 1975 Nov 20;410(1):145-55. doi: 10.1016/0005-2744(75)90215-6.
A strain of Bacillus sp (Bacillus R-4) produces a protease and a carbohydrolase both of which have the ability to lyse Rhizopus cell walls. Of the enzymes, the carbohydrolase has been purified to an ultracentrifugally and electrophoretically homogeneous state, and identified as a chitosanase. The enzyme was active on glycol chitosan as well as chitosan. Molecular weight of the purified enzyme was estimated as 31 000 and isoelectric point as pH 8.30. The enzyme was most active at pH 5.6 and at 40 degrees C with either Rhizopus cell wall or glycol chitosan as substrate, and was stable over a range of pH 4.5 to 7.5 at 40 degrees C for 3 h. The activity was lost by sulfhydryl reagents and restored by either reduced glutathione of L-cysteine. An abrupt decrease in viscosity of the reaction mixture suggested an endowise cleavage of chitosan by this enzyme.
一种芽孢杆菌属菌株（芽孢杆菌R - 4）可产生一种蛋白酶和一种碳水化合物酶，这两种酶都具有裂解根霉细胞壁的能力。在这些酶中，碳水化合物酶已被纯化至超速离心和电泳均一状态，并被鉴定为壳聚糖酶。该酶对乙二醇壳聚糖以及壳聚糖均有活性。纯化酶的分子量估计为31000，等电点为pH 8.30。以根霉细胞壁或乙二醇壳聚糖为底物时，该酶在pH 5.6和40℃时活性最高，在40℃下于pH 4.5至7.5范围内稳定3小时。巯基试剂会使酶活性丧失，而还原型谷胱甘肽或L - 半胱氨酸可使其恢复活性。反应混合物粘度的突然降低表明该酶对壳聚糖进行的是内切型裂解。
