title: The methyltrienolone binding protein of human placenta requires nicotinamide adenine dinucleotide cofactor(s) for steroid binding.
abstract: The methyltrienolone binding protein (MTBP) found in human placental cytosol was found to require a low molecular weight modulator for steroid binding activity. Purification and characterization of the modulating activity showed that NAD+ is the endogenous substance responsible for activating MTBP to a form capable of steroid binding. The hierarchy of potency of exogenously added nucleotides is NADH greater than NAD+ = NADPH = NADP+. An investigation of the tissue distribution of human MTBP demonstrated that MTBP binding activity was present in placenta and chorion but absent from amnion and umbilical cord. Preliminary studies showed that rat, mouse, and rabbit placenta do not contain MTBP and suggest that MTBP may be a species-specific protein.
authors.affiliation: Department of Endocrinology and Diabetes, Royal Children's Hospital, Parkville, Victoria, Australia.
authors.forename: J O
authors.initials: JO
authors.lastname: Macaulay
authors.forename: G L
authors.initials: GL
authors.lastname: Warne
authors.forename: A I
authors.initials: AI
authors.lastname: Smith
authors.forename: Z S
authors.initials: ZS
authors.lastname: Krozowski
mesh_terms: D000650:Amnion / Q000378:metabolism; D000727:Androgen-Binding Protein / Q000378:metabolism*; D000818:Animals; D002823:Chorion / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D005260:Female; D006801:Humans; D015741:Metribolone / Q000378:metabolism; D051379:Mice; D009243:NAD / Q000494:pharmacology*; D009249:NADP / Q000494:pharmacology; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D011817:Rabbits; D051381:Rats; D013045:Species Specificity; D014018:Tissue Distribution; D014470:Umbilical Cord / Q000378:metabolism
chemical_list: D000727:Androgen-Binding Protein; C028867:methyltrienolone binding protein, human; C488925:methyltrienolone binding protein, rat; D009243:NAD; D015741:Metribolone; D009249:NADP