PRIMARY STRUCTURE AND TISSUE DISTRIBUTION OF HUMAN 4-AMINOBUTYRATE AMINOTRANSFERASE

cDNA encoding human 4-aminobutyrate aminotransferase (aminobutyrate:2- oxoglutarate aminotransferase) was prepared by polymerase chain reacti on using mRNA from human neuroblastoma cells as the template and oligo nucleotides synthesized on the basis of the information obtained from direct protein sequencing. The cDNA-deduced sequence enabled peptides, sequenced by automated Edman degradation, to be aligned for confirmat ion of the complete primary structure. The results are compared with t he recently published sequence of the rat enzyme deduced entirely from DNA sequencing [Medina-Kauwe, L. K., Tillakaratne, N. J. K., Wu, J.-Y . and Tobin, A. J. (1994) J. Neurochem. 62, 1267-1275]. Although the s equences are almost identical for most of their length, they differ in a segment of 36 residues. Almost complete identity of the two sequenc es is established if it is assumed that a frame-shift error was introd uced into the reported rat cDNA sequence. The human cDNA was used to p robe for the presence of 4-aminobutyrate aminotransferase mRNA in huma n tissues and a significant transcript was found in heart, placenta an d in tissues usually associated with the expression of this enzyme.