BETAINE-HOMOCYSTEINE METHYLTRANSFERASE EXPRESSION IN PORCINE AND HUMAN TISSUES AND CHROMOSOMAL LOCALIZATION OF THE HUMAN GENE

We have prepared antibodies against porcine liver betaine-homocysteine methyltransferase (BHMT; EC 2.1.1.5) and recently cloned cDNAs encodi ng the porcine and human liver enzymes. Porcine tissues were evaluated for BHMT expression by measuring catalytic activity and Western analy sis, Liver and kidney were the only organs tested that had immunodetec table levels of BHMT, and these organs expressed high levels of enzyme activity. BHMT was expressed in the kidney cortex and not the medulla . Porcine pancreas, brain, heart, lung, and spleen were devoid of BHMT activity and immunodetectable protein Human tissues were tested for B HMT expression by Northern analysis, Human liver and kidney were the o nly organs tested that expressed BHMT mRNA. Human pancreas, brain, hea rt, skeletal muscle, spleen, and placenta were devoid of BHMT mRNA. Th e human BHMT gene has been mapped to chromosome 5q1.3.1-q15. (C) 1997 Academic Press.