Lee Y, Kim J W, Lee S M, Kim H J, Lee K S, Park C, Choe I S
Molecular and Cellular Biology Research Division, Korea Research Institute of Bioscience and Biotechnology, Taejon.
J Biochem. 1998 Jan;123(1):47-54. doi: 10.1093/oxfordjournals.jbchem.a021915.
A cDNA clone coding for adenylate kinase 2B was isolated from fetal liver, and the expression of AK2 was investigated in human tissues. The ORF in the cDNA clone for human AK2B predicted a protein comprising 232 amino acids (25.6 kDa). The features of AK2A and AK2B sequences in human were the same as those in the bovine system. Each of the recombinant proteins, AK2A and AK2B, was expressed in Escherichia coli cells, and the purified recombinant proteins were enzymatically active. The distribution of AK2 transcripts in various human tissues was examined by Northern analysis. Unlike in the bovine system, it was found that the AK2A transcript was the major form of AK2 mRNA species in all human tissues. The transcripts of AK2 isozymes were relatively abundant in heart, liver, and also in skeletal muscle, where the expression level of AK2 was known to be low. Western blot analysis of AK isozymes in human heart and skeletal muscle revealed that AK2 protein was found only in heart, whereas AK1 was detected in both tissues. These tissue-specific expressions of the AK isozymes in human might suggest the presence of organ-specific regulation of the AK2 gene including a post-transcriptional control in skeletal muscle.
从胎儿肝脏中分离出编码腺苷酸激酶2B的cDNA克隆，并研究了AK2在人体组织中的表达。人AK2B的cDNA克隆中的开放阅读框预测了一种由232个氨基酸组成的蛋白质（25.6 kDa）。人AK2A和AK2B序列的特征与牛系统中的相同。重组蛋白AK2A和AK2B均在大肠杆菌细胞中表达，纯化后的重组蛋白具有酶活性。通过Northern分析检测了AK2转录本在各种人体组织中的分布。与牛系统不同，发现AK2A转录本是所有人体组织中AK2 mRNA种类的主要形式。AK2同工酶的转录本在心脏、肝脏以及骨骼肌中相对丰富，而在骨骼肌中AK2的表达水平已知较低。对人心脏和骨骼肌中AK同工酶的蛋白质印迹分析表明，仅在心脏中发现了AK2蛋白，而在这两种组织中均检测到了AK1。人AK同工酶的这些组织特异性表达可能表明存在对AK2基因的器官特异性调控，包括骨骼肌中的转录后调控。
