Nonaka M, Sawa A, Matsuura Y, Motoki M, Nio N
a Food Research & Development Laboratories, Ajinomoto Co., Inc. , 1-1 Suzuki-cho, Kawasaki-ku, Kawasaki 210 , Japan.
Biosci Biotechnol Biochem. 1996 Jan;60(3):532-3. doi: 10.1271/bbb.60.532.
Enzymatic deamidation of αsl-casein was done by using Ca(2 +)-independent microbial transglutaminase (MTGase) of a variant of Streptoverticillium mobaraense. Although the amount of deamidated glutamine residues in αsl -casein was not as high as that of the case using guinea pig liver transglutaminase (GTGase), the improvements in pH-solubility and Ca(2 +)-sensitivity profile of the substrate protein were comparable to it. To do the enzymatic deamidation without chemical acylation of Lys residues of αsl- casein, several immobilized MTGase were prepared with two types of chitosan beads. Although neither αsl-casein nor β-casein was deamidated, dimethyl casein and citraconylated soy 7S globulin were deamidated by using the immobilized enzymes.
使用茂原链霉菌变种的钙独立型微生物转谷氨酰胺酶（MTGase）对αs1-酪蛋白进行酶促脱酰胺反应。尽管αs1-酪蛋白中脱酰胺谷氨酰胺残基的数量不如使用豚鼠肝脏转谷氨酰胺酶（GTGase）的情况高，但底物蛋白的pH溶解度和钙敏感性曲线的改善与之相当。为了在不使αs1-酪蛋白的赖氨酸残基发生化学酰化的情况下进行酶促脱酰胺反应，用两种类型的壳聚糖珠制备了几种固定化MTGase。尽管αs1-酪蛋白和β-酪蛋白均未发生脱酰胺反应，但使用固定化酶可使二甲基酪蛋白和柠康酰化大豆7S球蛋白发生脱酰胺反应。
