家蚕丝素蛋白胰凝乳蛋白酶沉淀物的分级分离。

Fractionation of the chymotryptic precipitate of Bombyx mori silk fibroin.

Zahn H, Schade W, Ziegler K

Biochem J. 1967 Sep;104(3):1019-26. doi: 10.1042/bj1041019.

Abstract

A solution of Bombyx mori silk fibroin was digested with chymotrypsin. Amino acid analyses of the chymotryptic precipitate showed in addition to the main constituents Gly, Ala, Ser and Tyr, very small amounts of Lys, His, Arg, Asp, Thr, Glu, Pro, Cys, Val, Met, Ile, Leu, Phe and Trp. 2. A stable solution of the chymotryptic precipitate in 6m-urea was obtained by dialysing a solution in 50% (w/v) lithium thiocyanate against 6m-urea. 3. The dinitrophenylated chymotryptic precipitate in 6m-urea was fractionated by gel filtration and by ion-exchange chromatography. On Dowex 1 (X2), a main fraction I(d) and three further fractions with different amino acid compositions and molecular weights were obtained. 4. Specific rearrangement and fission of the bonds involving the serine nitrogen atoms of fraction I(d) and fractionation of the resulting mixture by gel filtration yielded five fractions. Two of these fractions had the compositions DNP-Ser-(Gly(6),Ala(4),Ser) and DNP-Ser-(Gly(4),Ala(2) or Ala(3),Ser) and are presumably double repeating units according to the proposed formula of Lucas, Shaw & Smith (1957), namely Ser-Gly-(Ala-Gly)(n), for n values of 2 and 1 respectively.

摘要

用胰凝乳蛋白酶消化家蚕丝素蛋白溶液。对胰凝乳蛋白酶沉淀进行氨基酸分析，结果显示除了主要成分甘氨酸、丙氨酸、丝氨酸和酪氨酸外，还有极少量的赖氨酸、组氨酸、精氨酸、天冬氨酸、苏氨酸、谷氨酸、脯氨酸、半胱氨酸、缬氨酸、蛋氨酸、异亮氨酸、亮氨酸、苯丙氨酸和色氨酸。2. 通过将50%（w/v）硫氰酸锂溶液对6m尿素进行透析，得到了胰凝乳蛋白酶沉淀在6m尿素中的稳定溶液。3. 对6m尿素中的二硝基苯基化胰凝乳蛋白酶沉淀进行凝胶过滤和离子交换色谱分离。在Dowex 1（X2）上，得到了一个主要组分I(d)以及另外三个具有不同氨基酸组成和分子量的组分。4. 对涉及组分I(d)丝氨酸氮原子的键进行特定重排和断裂，并通过凝胶过滤对所得混合物进行分离，得到五个组分。其中两个组分的组成分别为DNP - 丝氨酸 -（甘氨酸(6)，丙氨酸(4)，丝氨酸）和DNP - 丝氨酸 -（甘氨酸(4)，丙氨酸(2)或丙氨酸(3)，丝氨酸），根据卢卡斯、肖和史密斯（1957年）提出的公式，推测它们可能是双重复单元，即丝氨酸 - 甘氨酸 -（丙氨酸 - 甘氨酸）(n)，n值分别为2和1。