| Literature DB >> 7142141 |
T L Walden, N Howes, W R Farkas.
Abstract
Guanine, queuine-tRNA transglycosylase has been purified from wheat germ to homogeneity. The specific activity is 2,000 pmol h-1 mg-1 of protein. The enzyme has an apparent Mr = 140,000. It migrates as a single band with Mr = 68,000 on electrophoresis in sodium dodecyl sulfate gels, indicating two Mr = 68,000 subunits. Both guanine (Km = 6.0 X 10(-8) M) and queuine (KI = 9.5 X 10(-8) M) are substrates but 7-(aminomethyl)-7-deazaguanine is not. The enzyme requires a monovalent or a divalent cation; Na+ and Mg2+ are more effective activators than other cations. The optimum pH is 7.6. Six tRNA isoacceptors found in wheat germ are substrates for the enzyme.Entities:
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Year: 1982 PMID： 7142141
Source DB: PubMed Journal: J Biol Chem ISSN： 0021-9258 Impact factor: 5.157