title: Association of folic acid with rat liver microsomes.
abstract: Shin et al. (Biochim Biophys Acta 444: 794-801, 1976) described the subcellular location of [3H]folic acid after injection into rats. The microsomal fraction of the liver contained relatively large amounts of tracer initially but lower amounts at later times. Because of the heterogeneous nature of the microsomal fraction of the liver we re-examined the nature of the folate binding fraction. The location of injected [3H]folic acid resembled that of the microsomes derived from the plasma membrane, where ultracentrifugal analysis was conducted in the presence and absence of cesium ions. The location of the folate did not resemble that of microsomes derived from the endoplasmic reticulum (ER). One of the marker enzymes of the ER was the vitamin K-dependent carboxylase. A simple method for reducing vitamin K is described.
authors.affiliation: Dept. of Nutritional Sciences, Univ. of California, Berkeley 94720.
authors.forename: T
authors.initials: T
authors.lastname: Brody
authors.forename: E L
authors.initials: EL
authors.lastname: Stokstad
mesh_terms: D000818:Animals; D015415:Biomarkers; D002262:Carboxy-Lyases / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism; D005492:Folic Acid / Q000378:metabolism*; D006867:Hydrolases / Q000378:metabolism; D008862:Microsomes, Liver / Q000201:enzymology / Q000378:metabolism*; D051381:Rats; D013379:Substrate Specificity; D014812:Vitamin K / Q000378:metabolism
chemical_list: D015415:Biomarkers; D014812:Vitamin K; D005492:Folic Acid; D003576:Electron Transport Complex IV; D006867:Hydrolases; D002262:Carboxy-Lyases