title: Biocytin synthetase activity in human milk as assessed by high-performance liquid chromatography.
abstract: A reversed-phase liquid chromatographic assay for biocytin synthetase activity has been developed. By this method, biocytin synthetase, isolated to homogeneity from human milk, was found to synthetize biocytin from biotin and L-lysine in the presence of ATP and magnesium ion(s). Both ATP and magnesium ion(s) were required for the synthesis of biocytin. Equal molar amounts of ADP and ATP were produced and consumed, respectively, in the course of the production of the same molar amount of biocytin; however, production of AMP was not observed. Biocytin synthetase Michaelis constants were 2.5, 1.8, and 0.11 mM for biotin, L-lysine, and ATP, respectively. Biocytin synthetase from milk was shown to synthesize biocytin in a stoichiometric amount.
authors.affiliation: National Children's Medical Research Center, Metabolism Research Laboratory, Tokyo, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Oizumi
authors.forename: K
authors.initials: K
authors.lastname: Hayakawa
mesh_terms: D000244:Adenosine Diphosphate / Q000032:analysis; D000249:Adenosine Monophosphate / Q000032:analysis; D000255:Adenosine Triphosphate / Q000378:metabolism; D000581:Amidohydrolases / Q000302:isolation & purification* / Q000378:metabolism; D000596:Amino Acids / Q000032:analysis; D043523:Biotinidase; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D007202:Indicators and Reagents; D007700:Kinetics; D008239:Lysine / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000378:metabolism; D008895:Milk, Human / Q000201:enzymology*
chemical_list: D000596:Amino Acids; D007202:Indicators and Reagents; D000249:Adenosine Monophosphate; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D000581:Amidohydrolases; D043523:Biotinidase; C013411:biocytin; D008239:Lysine