title: The role of the guanine insertion enzyme in O-biosynthesis in Drosophila melanogaster.
abstract: Drosophila tRNA can be guanylated by a crude enzyme from rabbit reticulocytes. Guanylating activity is also present in crude extracts of adult Drosophila. A major product of this reaction as well as several minor ones were resolved by RPC-5 chromatography. The main substrate of both the Drosophila and rabbit reticulocyte enzymes was the non-Q-containing aspartic acid tRNA, tRNA2gammaAsp. The QU-lacking (gamma) forms of asparagine, histidine and tyrosine tRNAs were also substrates and gave rise to the minor products of the reaction. In contrast, the Q- or Q*-containing (delta) forms of these tRNAs appear not to be substrates. The evidence strongly suggests that the guanyating enzyme is involved in Q biosynthesis and would be better termed a guanine replacement or pre-Q insertion enzyme.
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004331:Drosophila melanogaster / Q000378:metabolism*; D006147:Guanine; D006151:Guanosine / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000378:metabolism; D012343:RNA, Transfer / Q000096:biosynthesis; D014166:Transferases / Q000378:metabolism*
chemical_list: D006151:Guanosine; D006147:Guanine; D012343:RNA, Transfer; D014166:Transferases