Abstract: γ-32P adenosine triphosphate is exceedingly important substrate in the end-labeling and sepuencing of nucleic acids as well as in protein kinase reactions. It can also be used in the synthesis of 5'-32P-pCp, γ-32PATP is prepared from 1-α-glycerophosphate and ADP by a series of enzymatic reactions in the presence of NAD+ which is preferably regenerated by lactate dehydrogenase and pyruvate. The product is separated by ion-exchange column chromatography on DEAE-sephadex A-25 Cl- form or by the preparation chromatography. The radio-chemical purity obtained is 96-97% The yield of the product is>90% relative to 32P. The sample prepared by this method is comparable with the Amersham product. This method is rapid, simple and convenient.