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色氨酸酶是一种依赖磷酸吡哆醛的多功能酶,由相同的4个亚基组成,每个亚基含有一个磷酸吡哆醛结合位点,催化活性需要NH4+或K+存在。它不仅能催化L-色氨酸的分解,而且能催化一系列α,β-消去反应和β-取代反应。其催化机制主要包括外部醛亚胺的形成和醌型中间物的生成。在高浓度底物条件下,色氨酸酶能催化丙酮酸、吲哚和氨合成L-色氨酸。通过β-取代反应,色氨酸酶催化L-丝氨酸、L-半胱氨酸合成L-色氨酸,这为酶法工业化生产L-色氨酸提供了重要途径。此外,色氨酸酶在制备硫醇类香料化合物中也发挥重要作用。
Tryptophanase is a pyridoxal phosphate-dependent multifunctional enzyme consisting of the same four subunits, each containing a pyridoxal phosphate binding site, requiring catalytic activity in the presence of NH4 + or K +. It can not only catalyze the decomposition of L-tryptophan, but also catalyze a series of α, β-elimination reactions and β-substitution reactions. Its catalytic mechanism mainly includes the formation of external aldimine and the formation of quinoid intermediates. At high substrate concentrations, tryptophanases catalyze the synthesis of L-tryptophan from pyruvate, indole and ammonia. Tryptophanase catalyzes the synthesis of L-tryptophan by L-tryptophan and L-cysteine via β-substitution, which provides an important way for enzymatic industrial production of L-tryptophan. In addition, tryptophanase also plays an important role in the preparation of mercaptan flavor compounds.