必需氨基酸,从食物中摄取的色氨酸在许多代谢功能中起着至关重要的作用,具有广泛的生物学功能和应用。色氨酸通过提高营养成分和促进功能食品的发展对食品行业有益。编码色氨酸合酶的推定基因是在土壤鞘杆菌属Em02中首次鉴定的,该纤维质细菌使其固有地更环保。将该基因克隆并在外源宿主大肠杆菌中表达,阐明其功能。分子量为42KDa的重组色氨酸合酶以可溶性成分表达。使用吲哚和L-丝氨酸以及纯化的色氨酸合酶评估体内对色氨酸合酶的酶活性。色氨酸合酶的最佳酶活性记录在50ºC和pH7.0,在金属离子Mg2+的存在下得到改善,Sr2+和Mn2+,而Cu2+,Zn2+和Co2+被证明具有抑制作用。使用定点诱变,用K100Q证明了色氨酸合酶中HK-S-[GGGSN]-E-S的共有模式,S202A,G246A,E361A和S385A作为活性位点。色氨酸合酶已被证明具有β亚基的定义特征。色氨酸合酶最终可用于更大规模的色氨酸生产。其多样化的应用突出了提高食品的质量和健康益处的潜力,使其成为推进食品科学和技术的重要组成部分。
Essential amino acid, tryptophan which intake from food plays a critical role in numerous metabolic functions, exhibiting extensive biological functions and applications. Tryptophan is beneficial for the food sector by enhancing nutritional content and promoting the development of functional foods. A putative gene encoding tryptophan synthase was the first identified in Sphingobacterium soilsilvae Em02, a cellulosic bacterium making it inherently more environmentally friendly. The gene was cloned and expressed in exogenous host Escherichia coli, to elucidate its function. The recombinant tryptophan synthase with a molecular weight 42 KDa was expressed in soluble component. The enzymatic activity to tryptophan synthase in vivo was assessed using indole and L-serine and purified tryptophan synthase. The optimum enzymatic activity for tryptophan synthase was recorded at 50 ºC and pH 7.0, which was improved in the presence of metal ions Mg2+, Sr2+ and Mn2+, whereas Cu2+, Zn2+ and Co2+ proved to be inhibitory. Using site-directed mutagenesis, the consensus pattern HK-S-[GGGSN]-E-S in the tryptophan synthase was demonstrated with K100Q, S202A, G246A, E361A and S385A as the active sites. Tryptophan synthase has been demonstrated to possess the defining characteristics of the β-subunits. The tryptophan synthase may eventually be useful for tryptophan production on a larger scale. Its diverse applications highlight the potential for improving both the quality and health benefits of food products, making it an essential component in advancing food science and technology.