Human pyridoxal phosphatase - Molecular cloning, functional expression, and tissue distribution
Human pyridoxal phosphatase - Molecular cloning, functional expression, and tissue distribution
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DOI：
10.1074/jbc.m309619200
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发表时间：
2003-12-12
影响因子：
4.8
通讯作者：
Kwon, OS
中科院分区：
文献类型：
--
作者：
Jang, YM;Kim, DW;Kwon, OS
吡哆醛磷酸酶催化吡哆醛 5'-磷酸 (PLP) 和吡哆醇 5'-磷酸的去磷酸化。根据先前获得的肽序列，将人脑 cDNA 克隆鉴定为 PLP 磷酸酶。 cDNA 预测为 296 个氨基酸的蛋白质，计算出的 M-r 为 31698。开放阅读框由位于人类染色体 22q12.3 上的两个外显子编码，外显子-内含子连接处包含 GT/AG 共有剪接位点。此外，还分离出1978 bp的全长小鼠PLP磷酸酶cDNA。小鼠酶编码292个氨基酸的蛋白质，M-r为31512，定位于15.E1号染色体。人和小鼠 PLP 磷酸酶的蛋白质序列有 93% 的同一性。 BLAST 搜索揭示了从细菌到哺乳动物的生物体中存在推定蛋白质。在大肠杆菌中表达具有催化活性的人PLP磷酸酶，重组酶的特性与红细胞酶相似。重组酶显示吡哆醛的K-m 和k(cat) 值分别为2.5 muM 和1.52 s(-1)。人PLP磷酸酶mRNA以组织特异性方式差异表达。在所有检查的人体组织中都检测到了 2.1 kb 的单个 mRNA 转录物，并且在大脑中含量很高。获得人类 PLP 磷酸酶的分子特性可能为研究涉及维生素 B-6 的代谢途径提供新的方向。
Pyridoxal phosphatase catalyzes the dephosphorylation of pyridoxal 5'-phosphate (PLP) and pyridoxine 5'-phosphate. A human brain cDNA clone was identified to the PLP phosphatase on the basis of peptide sequences obtained previously. The cDNA predicts a 296-amino acid protein with a calculated M-r of 31698. The open reading frame is encoded by two exons located on human chromosome 22q12.3, and the exon-intron junction contains the GT/AG consensus splice site. In addition, a full-length mouse PLP phosphatase cDNA of 1978 bp was also isolated. Mouse enzyme encodes a protein of 292 amino acids with M-r of 31512, and it is localized on chromosome 15.E1. Human and mouse PLP phosphatase share 93% identity in protein sequence. A BLAST search revealed the existence of putative proteins in organism ranging from bacteria to mammals. Catalytically active human PLP phosphatase was expressed in Escherichia coli, and characteristics of the recombinant enzyme were similar to those of erythrocyte enzyme. The recombinant enzyme displayed K-m and k(cat) values for pyridoxal of 2.5 muM and 1.52 s(-1), respectively. Human PLP phosphatase mRNA is differentially expressed in a tissue-specific manner. A single mRNA transcript of 2.1 kb was detected in all human tissues examined and was highly abundant in the brain. Obtaining the molecular properties for the human PLP phosphatase may provide new direction for investigating metabolic pathway involving vitamin B-6.