THE OXIDATION OF PROTEINS AND MODEL POLYMERS

丙氨酸、精氨酸、组氨酸、赖氨酸和组氨酸的L-异构体的均聚物 脯氨酸在亚铁和螯合剂的存在下被氧化， 通常是柠檬酸盐。聚合物的氧化引入羰基，其可 可通过与2，4-二硝基苯肼或 在氰基硼氢化钠的存在下，对氨基苯甲酸。氧化 导致这些均聚物的酸沉淀性损失。当类似 用胰岛素β链进行氧化，类似的氧化 变化：羰基含量增加，沉淀减少 酸。胰岛素β链的氨基酸分析表明， 对肽残基的攻击必须是随机的。

Homopolymers of L-isomers of alanine, arginine, histidine, lysine, and proline have been oxidized in the presence of ferrous iron and a chelator, generally citrate. Oxidation of the polymers introduces carbonyls which may be detected by reaction with 2,4-dinitrophenylhydrazine or with p-aminobenzoic acid in the presence of sodium cyanoborohydride. Oxidation results in loss of acid precipitability of these homopolymers. When similar oxidations were conducted with insulin beta chain, similar oxidative changes are seen: increased carbonyl content and decreased precipitation with acid. Amino acid analysis of the insulin beta chain suggests that the attack on the peptide's residues must be random.