1. We describe the use of benzyloxycarbonylmethionine and ethoxycarbonylmethionine for the selective protection of the amino groups of glycine-A1 and lysine-B29 of pig insulin. We have used the Edman method to remove residues from the N-terminal and of the B-chain of the N(A1)N(B29)-di-protected derivatives. The benzyloxycarbonyl group shows slight but noticeable lability in the acid-cleavage step, but the ethoxycarbonyl group remained intact even after five cycles of degradation. 2. We have prepared the following truncated forms of insulin via the di(ethoxycarbonylmethionyl) derivativedes-Phe(B1)-insulin;des-(Phe(B1)-Val(B2))-insulin; des-(Phe(B1)-Val(B2)-Asn(B3))-insulin;des- (Phe(B1)-Val(B2)-Asn(B3)-Gln(B4))-insulin; des-(Phe(B1)-Val(B2)-Asn(B3) -Gln(B4)-His(B5))-insulin. 3. Insulin was re-synthesized from the di-protected des-Phe(B1)-insulin by reaction with an active ester of t-butoxycarbonyl-l-phenylalanine. The product after deprotection crystallized, and the immunoreactivity of the crystalline material was identical with that of the native protein. 4.

We have prepared the following analogues of insulin in a similar manner[l-Ala(B1)]insulin; [l-Val(B1)]insulin; [l-Tyr(B1)]insulin; [m-F-l-Phe(B1)]insulin; [o-F-l-Phe(B1)]-insulin; [o-F-l-Phe(B2)]des-Phe(B1)-insulin. All had between 34 and 62% of the activity of insulin in the fat-cell test. 5. We have also investigated the use of the benzyol, toluene-p-sulphonyl, p-nitrobenzyloxycarbonyl and 2,4-dinitrophenyl groups for the N-protection of the methionine active esters. Each should have had some particular advantage over the benzyloxycarbonyl and ethoxycarbonyl groups, but all proved in practice to have disadvantages that more than outweighed anything in their favour.

译文

1.我们描述了使用苄氧羰基蛋氨酸和乙氧羰基蛋氨酸选择性保护猪胰岛素的甘氨酸-A1和赖氨酸-B29的氨基。我们已经使用Edman方法从N(A1)N(B29)-di-protected衍生物的N末端和B链中去除残基。苄氧基羰基在酸裂解步骤中显示出轻微但明显的不稳定性,但是即使经过五个降解循环,乙氧基羰基仍保持完整。 2.我们通过二(乙氧基羰基甲硫酰基)衍生物des-Phe(B1)-胰岛素; des-(Phe(B1)-Val(B2))-胰岛素制备了以下截短形式的胰岛素; des-(Phe(B1)-Val(B2)-Asn(B3))-胰岛素; des-(Phe(B1)-Val(B2)-Asn(B3)-Gln(B4))-胰岛素; des-(Phe(B1)-Val(B2)-Asn(B3)-Gln(B4)-His(B5))-胰岛素。 3.通过与叔丁氧羰基-1-苯基丙氨酸的活性酯反应,从双保护的des-Phe(B1)-胰岛素重新合成胰岛素。脱保护后的产物结晶,并且该结晶物质的免疫反应性与天然蛋白质的免疫反应性相同。 4.
我们以相似的方式制备了以下胰岛素类似物[1-Ala(B1)]胰岛素; [l-Val(B1)]胰岛素; [1-Tyr(B1)]胰岛素; [m-F-1-Phe(B1)]胰岛素; [o-F-1-Phe(B1)]-胰岛素; [o-F-1-Phe(B2)] des-Phe(B1)-胰岛素。在脂肪细胞试验中,所有人的胰岛素活性在34%至62%之间。 5.我们还研究了苯甲酚,甲苯-对-磺酰基,对-硝基苄氧基羰基和2,4-二硝基苯基用于甲硫氨酸活性酯的N-保护。每种化合物都应比苄氧羰基和乙氧羰基有一些特殊的优点,但是在实践中所有这些都被证明具有弊端,胜过任何对它们有利的事情。

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