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本文给出胰岛素和去B链羧端五肽胰岛素(DPI)紫外光解的原初产物的瞬态吸收光谱,并与游离态酪氨酸进行比较.光谱的远紫外区(<300毫微米)未见有过报道.胰岛素和DPI的原初光产物主要是对位α-氨基丙酸苯氧自由基(λ_(max)=410,390毫微米)和另一种未知自由基(λ_(max)=270毫微米),它们的产额与酪氨酸残基酚环上羟基的解离率平行对应,而解离率又依赖于残基的暴露程度.实验测定了胰岛素和DPI光解产生苯氧型自由基的量子产额并与游离态酪氨酸比较,给出了这两种蛋白质分子中光易变的酪氨酸残基数,这个光易变性参数将为胰岛素和DPI分子中酪氨酸残基的暴露情况提供较定量的信息。
This article presents the transient absorption spectra of the primary products of insulin and the UV photodissociation of the B-terminal carboxy-terminal pentapeptide insulin (DPI) and comparison with free tyrosine. The far ultraviolet region (<300 nm) of the spectrum was not seen It has been reported that the primary photoproducts of insulin and DPI are primarily the p-phenylalanyl α-alanine (λ max = 410,390 nm) and another unknown free base (λ max = 270 nm ), Their yields corresponded in parallel to the dissociation rates of hydroxyl groups on the phenolic ring of tyrosine residues, which in turn depend on the degree of residue exposure.Detection of insulin and DPI photolysis to produce phenoxy-type free radicals Of the quantum yield and compared with the free tyrosine gives the number of light-labile tyrosine residues in both protein molecules that will be the sum of the tyrosine residues in insulin and DPI molecules Exposure provides more quantitative information.