Asparagine Synthetase Activity in Malignant and Non-malignant Human Kidney and Prostate Specimens

NUMEROUS studies have demonstrated the anti-tumour activity of L-asparaginase. Although most of the studies have been performed with enzyme from guinea-pig serum or E. coli , asparaginases from other sources are also inhibitory. A mechanism based on data from several laboratories 1–4 has been suggested to account for the anti-tumour activity of the enzyme. A tumour with little or no capacity to synthesize asparagine must be supplied through the circulation. When asparaginase is introduced into the blood stream, asparagine levels quickly fall 5 , and the tumour starves for lack of one of its essential nutrients. On the other hand, if a tumour can synthesize asparagine, it should be resistant to asparaginase action.