Investigation of physiological functions of a 3-mercaptopyruvate sulfurtransferase

1. 通过cDNA和纯化酶的序列分析，确定了人肝脏3-巯基丙酮酸硫转移酶（3-MST,EC2.8.1.2）的完整氨基酸结构。该酶由297个氨基酸残基组成，计算分子质量为33,176.7道尔顿。人类3-MST与rhodanese在cDNA序列和推导出的氨基酸序列上的一致性分别为66.9和59.7%。通过3-MST与rhodanese的全序列相似性，证实3-MST与rhodanese是进化相关的酶。当3-MST cDNA在大肠杆菌和Cos7细胞中短暂表达时，3-MST活性分别提高了20倍和45倍。从人胎儿肝脏cDNA文库中克隆人罗丹斯硫代硫酸盐氰化物硫转移酶（ec2.8.1.1） cDNA。cDNA测序显示一个开放阅读框，编码297个残基的多肽，计算质量为33427道尔顿。当rhodanese cDNA在大肠杆菌和Cos7细胞中短暂表达时，rhodanese活性分别提高了40倍和150倍。序列同源性分析表明，人类罗丹尼斯人与牛的同源性为89.6%，与大鼠的同源性为90.2%，与小鼠和中国仓鼠的同源性为91.2%，与鸟类的同源性为71.4%，具有高度的保守性。

1. A complete amino acid structure of human liver 3-mercaptopyruvate sulfurtransferase (3-MST,EC2.8.1.2) was determined by sequence analysis of cDNA and purified enzyme. The enzyme consists of 297-amino acid residues with a calculated molecular mass of 33,176.7daltons. Sequence identity in cDNA and the deduced amino acid sequence are 66.9 and 59,7% respectivity, between human 3-MST and rhodanese. By their entire sequence similarity 3-MST and rhodanese are confirmed to be evolutionarily related enzyme. When the 3-MST cDNA was transiently expressed in Escherchia coli and Cos7 cells, the 3-MST activity increased 20-fold and 45-fold, respectively.2. cDNA for the human rhodanese (thiosulfate ; cyanide sulfurtransuferase, EC 2.8.1.1) was cloned from a human fetal liver cDNA library. Sequencing of the cDNA revealed an open reading frame that encodes a 297-residue polypeptide with a calculated mass of 33427 daltons. When the rhodanese cDNA was transiently expressed in Escherchia coli and Cos7 cells, the rhodanese activity increased 40-fold and 150-fold, respectively. Sequence homology analysis showed that the human rhodanese is 89.6% identical to bovine, 90.2% identical to rat, 91.2% identical to mouse and Chinese hamster, and 71.4% similar to avian counterparts, respectively, and that rhodanese was highly conserved across evolution.