The synthesis of glycyl-l-phenylalanyl-sRNA

Glycyl-l-phenylalanyl-sRNA was prepared by acylation of l-phenylalanyl-sRNA. The method involves the use of N-hydroxysuccinimide ester of N-protected glycine as a highly specific reagent which acylates only the amino group of the phenylalanine bound to the sRNA and does not react with any of the functional groups of sRNA. The amino group of glycine was protected with mono-p-methoxytriphenylmethyl. This protecting group was found to be stable during the acylation reaction and could be removed from the dipeptidyl-sRNA under very mild conditions (5 % trichloroacetic acid for 5 min at 4°), leaving the sRNA intact.