Primary structure of a human trifunctional enzyme. Isolation of a cDNA encoding methylenetetrahydrofolate dehydrogenase-methenyltetrahydrofolate cyclohydrolase-formyltetrahydrofolate synthetase.

摘要: A DNA clone complementary to the messenger RNA encoding human trifunctional enzyme 5,10-methylenetetrahydrofolate dehydrogenase-5,10-methenyl-tetrahydrofolate cyclohydrolase-10-formyltetrahydrofolate synthetase has been isolated from a lambda gt10 library. In vitro transcription-translation of 3.1-kilobase cDNA yields protein 101 kDa, which is identical size and exhibits same immunoreactivity as purified liver. coding region 2805 base pairs in encodes 935 amino acids. The initiator methionine absent amino-terminal 30 acids derived by automated sequence analysis are (arginine at position 18 was not identified) with that deduced nucleotide sequence. acid shows extensive homology yeast enzyme, although bifunctional dehydrogenase-cyclohydrolase domain less homologous than carboxyl-terminal domain. identified probably serves link between these two major domains enzyme. contains regions consensus sequences for an ATP-binding site.