Trimethyllysine Hydroxylase Epsilon (TMLHe)

Epsilon-N-trimethyllysine hydroxylase (EC 1.14.11.8) catalyzes the conversion of epsilon-N-trimethyllysine to beta-hydroxy-N-epsilon-trimethyllysine in the first step of L-carnitine biosynthesis.The deduced 421-amino acid human TMLHE and 405-amino acid rat Tmlhe proteins have calculated molecular masses of 49.5 kD and 47.5 kD, respectively, and share 92% amino acid identity. Subcellular fractionation localized rat Tmlhe to mitochondria. Rat Tmlhe was synthesized as a 47.5-kD precursor that is processed to an approximately 43-kD protein, most likely through cleavage of a mitochondrial targeting signal. Gel filtration analysis showed rat Tmlhe as an 87-kD band, suggesting that Tmlhe forms a homodimer.