Purification, cDNA cloning and expression of human NG,NG-dimethylarginine dimethylaminohydrolase

cDNA encoding N-G,N-G-dimethylarginine dimethylaminohydrolase from rat kidney had been cloned [Kimoto, M., Sasakawa, T, Tsuji, H., Miyatake, S., Oka, T, Nio, N. & Ogawa, T. (1997) Biochim. Biophys. Acta 1337, 6-10]. The enzyme hydrolyzes N-G,N-G-dimethyl-L-arginine and N-G-monomethyl-L-arginine, which are known as endogenous inhibitors for the nitric oxide-generating system. In the present study, human N-G,N-G-dimethylarginine dimethylaminohydrolase has been purified to homogeneity from liver and characterized. The cDNA clone encoding human NG,NG-dimethylarginine dimethylaminohydrolase was isolated from a human kidney lambda gt10 library using a probe prepared from a plasmid containing the entire coding region of rat N-G,N-G-dimethylarginine dimethylaminohydrolase. Its open reading frame encoded a protein of 285 amino acids with a molecular mass of 31 121 Da. The deduced amino acid sequence exhibits 93% identity with that of rat. The cDNA was expressed as a fusion protein in Escherichia coli and the recombinant protein exhibited enzyme activity which is the same as that of natural enzyme.