Tsykerovich A S, Kastrikina T F, Karpenko G F
Ukr Biokhim Zh. 1976 Apr-Jun;48(3):355-9.
The ariticle deals with gelatin hydrolysis by the crystalline preparation of the Str. griseus protease. 12.1% of 1080 peptide bonds available in 105 g of protein split for 24 h at 40 C. The bonds of 8-9 types which involve N-end of glycine, serine, phenylalanine, threonine, leucine, valine, glutaminic acid, lysine break at once. The process occurs with delay, and 0.25, 0.5, 6 and 24 h after there occurs a breakage of the 42d, 61st, 117th and131st bonds. The middle size of the peptide chain of the initial protein is 604 amino acid residues, in the hydrolyzate 30, 22, 11.6 and 11.3 residues are found within these intervals, respectively. Main changes occur in the fraction of soluble peptides where number of N-terminal amino acids rises from 25 to 80. Some data are obtained on the total specificity of the Str. griseus protease. It splits mostly the bonds which involve the N-end of glycine (51%), alanine 2%), serine (9%). The content of the definite amino acid in gelatin shows that hydrolysis bonds of serine and threonine accounts for 35.2 and 35.6%, valine and leucine for 23.6 and 24.7%, glycine and alanine for 18.8 and 13%, methionine, lysine, glutaminic and asparagic acids for 7-9%; the proline bonds are not splitted at all. An assumption is advanced on the presence of four groups of bonds in gelatin; the rate of their hydrolysis corresponding to the enzyme specificity. The Str. griseus protease splits as free amino acids 10 mol of serine of 35,5, 5.5 mol of leucine of 26.3, 3.6 mol of threonine of 19.8 and only 4 mol of glycine of 363 available in gelatin.
本文研究了灰色链霉菌蛋白酶结晶体制剂对明胶的水解作用。在40℃下，105克蛋白质中1080个肽键的12.1%在24小时内被裂解。涉及甘氨酸、丝氨酸、苯丙氨酸、苏氨酸、亮氨酸、缬氨酸、谷氨酸、赖氨酸N端的8 - 9种类型的键会立即断裂。该过程有延迟，在第42个、61个、117个和131个键断裂后0.25小时、0.5小时、6小时和24小时发生。初始蛋白质肽链的中间大小为604个氨基酸残基，在水解产物中，在这些区间分别发现30个、22个、11.6个和11.3个残基。主要变化发生在可溶性肽部分，其中N端氨基酸的数量从25个增加到80个。获得了一些关于灰色链霉菌蛋白酶总特异性的数据。它主要裂解涉及甘氨酸N端（51%）、丙氨酸（2%）、丝氨酸（9%）的键。明胶中特定氨基酸的含量表明，丝氨酸和苏氨酸的水解键分别占35.2%和35.6%，缬氨酸和亮氨酸占23.6%和24.7%，甘氨酸和丙氨酸占18.8%和13%，蛋氨酸、赖氨酸、谷氨酸和天冬氨酸占7 - 9%；脯氨酸键根本不被裂解。提出了关于明胶中存在四组键的假设；它们的水解速率与酶的特异性相对应。灰色链霉菌蛋白酶将明胶中35.5的10摩尔丝氨酸、26.3的5.5摩尔亮氨酸、19.8的3.6摩尔苏氨酸以及仅363的4摩尔甘氨酸裂解为游离氨基酸。
