Ichida K, Amaya Y, Noda K, Minoshima S, Hosoya T, Sakai O, Shimizu N, Nishino T
Department of Biochemistry, Yokohama City University School of Medicine, Japan.
Gene. 1993 Nov 15;133(2):279-84. doi: 10.1016/0378-1119(93)90652-j.
The primary structure of human xanthine dehydrogenase (hXDH) was determined by cloning and sequence analysis of the cDNAs encoding the enzyme. The nucleotide (nt) sequence has an open reading frame of 3999 nt encoding a protein of 1333 amino acids (aa) with a calculated M(r) of 146,604. The deduced aa sequence of hXDH is homologous to the previously reported rat XDH (rXDH) and Drosophila melanogaster XDH sequences with identities of 90.2 and 52.0%, respectively. The aa residues involved in both the reversible and the irreversible conversion from the dehydrogenase type to the oxidase type of rXDH are completely conserved between the rat and the human enzymes. This implies that the molecular mechanisms of the conversion of hXDH from dehydrogenase to oxidase are common to those of the well-characterized rXDH. Five sequence variations were detected in the isolated cDNA clones. Spot blot hybridization using flow-sorted human chromosome revealed that the hXDH-encoding gene (hXDH) was located on chromosome 2.
通过对编码该酶的cDNA进行克隆和序列分析，确定了人黄嘌呤脱氢酶（hXDH）的一级结构。核苷酸（nt）序列有一个3999 nt的开放阅读框，编码一个1333个氨基酸（aa）的蛋白质，计算所得的分子量（M(r)）为146,604。推导的hXDH氨基酸序列与先前报道的大鼠XDH（rXDH）和黑腹果蝇XDH序列同源，同源性分别为90.2%和52.0%。在大鼠和人酶之间，参与rXDH从脱氢酶型向氧化酶型可逆和不可逆转化的氨基酸残基完全保守。这意味着hXDH从脱氢酶向氧化酶转化的分子机制与已充分表征的rXDH的机制相同。在分离的cDNA克隆中检测到五个序列变异。使用流式细胞仪分选的人染色体进行斑点杂交显示，编码hXDH的基因（hXDH）位于2号染色体上。
