Transfer RNA methyltransferases from yellow lupin seeds: purification and properties.

tRNA methyltransferases from extract of yellow lupin seeds were purified over 300-fold by the methods based on hydrophobic and affinity chromatography. However, in the most active fractions the methylating enzymes were over 2000 purified. The purified enzyme fractions catalysed the formation of 1-methyladenine and 5-methylcytosine using E. coli B and B. subtilis tRNAs as substrates and S-adenosylmethionine as the methyl donor. They were unable to methylate their own endogenous tRNA but they were capable of methylating tRNA of some other lupinus species. Whereas the patterns of methylated constituents of tRNA of some other lupinus and B. subtilis were quite similar, they differed considerably from those obtained with lupin species tRNAs. Some properties of purified methyltransferases from yellow lupin seeds have been described.