coli tRNA showed that, in the case of the liver tumors, the increased formation of N 2- dimethylguanine was much greater than that of the other methyl bases. With the kidney tumor, a similar change in the pattern of methylation was obtained. Extracts of liver regenerating after partial ...
In each case N 2-methylguanine and N 2, N 2-dimethylguanine represented 90% or more of the products of these in vitro methylations. The product and substrate specificity observed are characteristic of N 2-guanine methyltransferase II ( S- adenosyl- L- methionine:tRNA (guanine-2)-...
One catalyzes the methylation of adenine residues of the tRNA to give 1-methyladenine units and the other is responsible for the conversion of guanine residues to N 2-methylguanine and N 2,N 2-dimethylguanine (and may be a mixture of two enzymes). Activities of these relatively unstable ...