EFFECT OF AMINOACYL TRANSFER RIBONUCLEIC ACID ON COMPETITION BETWEEN GUANOSINE 5'-TRIPHOSPHATE AND GUANOSINE 5'-DIPHOSPHATE FOR BINDING TO A POLYPEPTIDE CHAIN ELONGATION FACTOR FROM EXCHERICHIA COLI

The polypeptide chain elongation factor preparation referred to as T (an undissociated combination of Tu and Ts) exhibited preferential binding of guanosine 5′-diphosphate, even in the presence of a large excess of guanosine 5′-triphosphate, when tested for retention on Millipore filters. Previously published data on binding of guanosine 5′-triphosphate using this assay is now shown to be attributable to the preferential binding of the [3H]guanosine 5′-diphosphate present in the [3H]guanosine 5′-triphosphate preparation. Removal of this guanosine 5′-diphosphate with a guanosine 5′-triphosphate regenerating system considerably reduced the level of bound nucleoside phosphate. Nonradioactive guanosine 5′-triphosphate did not compete with Millipore-bindable [3H]guanosine 5′-diphosphate. Addition of aminoacyl transfer ribonucleic acid reversed this preference for guanosine 5′-diphosphate. © 1969, American Chemical Society. All rights reserved.