title: The size and distribution of cytochrome c oxidase subunit IV mRNA between free and membrane-bound polyribosomes.
abstract: A length of 990 +/- 80 nucleotides was estimated for the poly(A)-rich mRNA in the higher-molecular-weight precursor of rat liver cytochrome c oxidase subunit IV. Assuming a molecular weight of 19500 for the cytochrome c oxidase subunit IV precursor, a non-coding region of about 350 nucleotides must exist. In experiments on the site of synthesis it is shown that the poly(A)-rich RNA for the higher-molecular-weight precursor of cytochrome c oxidase subunit IV is found in free, loosely and tightly membrane-bound polyribosomes. This finding does not agree with the present picture of free polysomes as the exclusive site of synthesis for mitochondrial proteins.
mesh_terms: D000818:Animals; D001665:Binding Sites; D002462:Cell Membrane / Q000201:enzymology; D003576:Electron Transport Complex IV / Q000096:biosynthesis*; D004792:Enzyme Precursors / Q000378:metabolism; D008099:Liver / Q000201:enzymology; D008297:Male; D011061:Poly A / Q000378:metabolism; D011132:Polyribosomes / Q000201:enzymology*; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D013347:Subcellular Fractions / Q000201:enzymology
chemical_list: D004792:Enzyme Precursors; D012333:RNA, Messenger; D011061:Poly A; D003576:Electron Transport Complex IV