Veronese F M, Fontana A, Boccù E
Acta Vitaminol Enzymol. 1975;29(1-6):243-7.
Upon reaction of tryptophan containing proteins with 2-nitrophenylsulfenyl chloride (NPS-Cl) the nitroaryl chromphore (lambda max 365 nm, epsilon 4000) is covalently linked at the 2-position of the indole ring of tryptophan. From the mixture of peptides obtained by enzymatic or chemical fragmentation of the labelled protein, the yellow tryptophan peptides are much more easily separated by column as well as paper chromatographic techniques, since their easier detection by spectrophotometry. Tryptophan peptides have been also isolated by diagonal electrophoresis, upon introduction of a carboxylate anion in the peptide by reaction with the carboxy-substituted reagent 2-nitro-4-carboxyphenylsulfenyl chloride. Sulfenl halides have been also used for the selective chemical coupling of tryptophan peptides to a solid support, thus facilitating their separation. N-acetyl-tryptophan has been covalently coupled to an amino-resin (aminoethylated Bio-Gel), and the resulting polymer reacted with a mixture of peptides in presence of 4,6-dinitrophenyl-1,3-disulfenyl chloride in glacial acetic acid. Selective covalent binding of tryptophan peptides has been checked.
当含色氨酸的蛋白质与2-硝基苯磺酰氯（NPS-Cl）反应时，硝基芳基发色团（最大吸收波长365nm，摩尔吸光系数4000）共价连接到色氨酸吲哚环的2位。从通过标记蛋白质的酶促或化学裂解获得的肽混合物中，黄色色氨酸肽通过柱色谱和纸色谱技术更容易分离，因为它们通过分光光度法更容易检测。通过与羧基取代试剂2-硝基-4-羧基苯磺酰氯反应在肽中引入羧酸根阴离子后，色氨酸肽也已通过对角线电泳分离。磺酰卤也已用于色氨酸肽与固体支持物的选择性化学偶联，从而便于它们的分离。N-乙酰色氨酸已共价偶联到氨基树脂（氨乙基化的生物凝胶）上，所得聚合物在冰醋酸中与4,6-二硝基苯基-1,3-二磺酰氯存在下与肽混合物反应。已检查色氨酸肽的选择性共价结合。
