Myshunin I F, Tsyperovych O S, Kuznetsova I M
Ukr Biokhim Zh. 1975 Mar-Apr;47(2):226-32.
Hydrolysis of collagen was studied in the bull bone tissues by the Str. griseus crystalline protease. The amount of collagen hydrolyzed by it composed 6.6% and 16% after 4-hour and 6-hour hydrolysis, respectively. When the enzyme:substrate ratio is 1:50 hydrolysis proceeds most intensively; with a decrease in the ratio up to 1:1000 the average amount of peptides increase from 2.6 up to 4 amino acidic residua, respectively. Under conditions of denaturated collagen hydrolysis the content of hydroxyproline in solution as compared with the native one increases; in this case the links with the presence of imino-acids are easier to split, the more resistant being those formed by hydroxyproline. Within the limit of 20-45 degrees C hydrolysis of protein intensifies with a temperature rise. Within the pH range of 5.0-11.0 the maximal amount of alpha- NH2-groups and hydroxyproline is observed at pH 8.5, the minimal--at PH 5.0. Hydroxyproline in the composition of peptides appears at the beginning of hydrolysis whereas the free one of enzymes of the longer effect 24 h after the beginning of the experiment composes 12.2% of its total content in the solved products. In the insoluble part of the substrate after 3-hour hydrolysis tyrosine composes less than 25% of its initial amount in protein whereas phenyl alanine--over 70%. After 6-hour hydrolysis the solved part of the system contains about 30% of alanine and 8.9 and 6% of glycine, proline and hydroxyproline, respectively.
用灰色链霉菌结晶蛋白酶研究了牛骨组织中胶原蛋白的水解情况。经4小时和6小时水解后,被该酶水解的胶原蛋白量分别为6.6%和16%。当酶与底物的比例为1:50时,水解进行得最为剧烈;当比例降至1:1000时,肽的平均量分别从2.6个氨基酸残基增加到4个氨基酸残基。在变性胶原蛋白水解条件下,与天然胶原蛋白相比,溶液中羟脯氨酸的含量增加;在这种情况下,与亚氨基酸存在相关的键更容易断裂,而由羟脯氨酸形成的键更具抗性。在20至45摄氏度范围内,蛋白质的水解随着温度升高而加剧。在pH值5.0至11.0范围内,在pH 8.5时观察到α-NH2-基团和羟脯氨酸的量最大,在pH 5.0时最小。肽组成中的羟脯氨酸在水解开始时出现,而在实验开始24小时后,较长时间作用的酶的游离羟脯氨酸占其在水解产物中总含量的12.2%。在3小时水解后,底物的不溶性部分中酪氨酸占其在蛋白质中初始量的不到25%,而苯丙氨酸超过70%。6小时水解后,体系的水解部分分别含有约30%的丙氨酸、8.9%的甘氨酸、6%的脯氨酸和羟脯氨酸。