Biochemical Studies of the Nucleoside Analogue, Formycin

Abstract

Abstract The absorption and fluorescence properties of formycin provide a useful tool in the analysis of enzyme-substrate interactions; we have therefore studied selected biochemical properties of formycin nucleotides. Formycin and its derivatives effectively substitute for the corresponding adenosine substrates in a wide variety of enzyme reactions. These include enzymes of nucleotide metabolism, RNA polymerase, polynucleotide phosphorylase, aminoacyl-transfer RNA synthetases, and the pyrophosphorylase of tRNA. tRNA molecules bearing formycin nucleoside termini are readily aminoacylated and efficiently transfer amino acids into polypeptides. Polymers containing formycin have also been prepared and studied. Certain characteristics of these polynucleotides are paradoxical. Copolymers of formycin are readily synthesized by polymerizing enzymes and efficiently direct polypeptide synthesis in vitro, while the homopolymer of formycin is difficult to synthesize and is inactive in coding experiments.