The Enzymic Synthesis of Amino Acyl Derivatives of Ribonucleic Acid

Phenylalanyl transfer ribonucleic acid synthetase from Escherichia coli. Reaction parameters and order of substrate addition

“…employed in this study, ATP-PP, exchange is some 40-fold more rapid than acylation of tRNAphe. This difference is of the same order as observed for the Leuand Tyr-tRNA synthetase (Calendar and Berg, 1966;Berg et al, 1961) from E. coli. Using the reported molecular weight of 181,000 (Kosakowski and Bock, 1970;Stulberg, 1967) and homogeneity of 85% for our enzyme preparation, catalytic constants of 4200 and 105 moles per min per mole of PRS may be calculated for ATP-PPi exchange and Phe-tRNA formation, respectively.…”

The Mechanism of Hydrolysis of Amino Acyl RNA*

“…The chemical properties of amino acid esters have attracted increasing interest since the discovery that such esters are intermediates in protein synthesis (Hoagland et al, 1957;Zachau et al, 1958). The high free energy of hydrolysis of amino acid esters of soluble RNA at physiological pH (Berg et al, 1961;Lipmann et al, 1959;Allen et al, 1960;Leahy et al, 1960) has been shown to be a general property of amino acid esters and arises from destabilization, by the positively charged -ammonium group, of the ester relative to the acid released by hydrolysis (Jencks et al, 1960).…”

Experiments on the Mechanism of Gramicidin and Tyrocidine Synthesis in Cell-free Preparations of Bacillus brevis*

“…Also, 40 µg of pyruvic kinase and 5 mM phosphoenolpyruvate were present. At the end of the incubation period the labeled aminoacyl-s-RNA was precipitated (without addition of carrier) by adding 0.4 ml of 20% sodium acetate plus 10 ml of ethanol, and was washed and dried, as described by Berg et al (1961). The product (approximately 18 mg) was stored at -20°, and was stable for at least a week.…”