An activity that binds preferentially to depurinated DNA and inserts purines into those sites was partially purified from Drosophila melanogaster embryos. The protein has a sedimentation coefficient of 4.9 S and is devoid of AP (apurinic/apyrimidinic) endonuclease activity. Upon incorporation of purines into apurinic DNA, the number of alkali-labile sites decreases, thus establishing the conver...

Nucleotide metabolism results in the synthesis of the four nucleotides that form DNA. These are further divided in two categories: purines and pyrimidines. Their construction and degradation takes place in a progression of single steps, while different enzymes and cofactors are involved in the process. Beside degradation, there is also a form of reprocessing purine and pyrimidine nucleotides, d...

Nucleotide metabolism results in the synthesis of the four nucleotides that form DNA. These are further divided in two categories: purines and pyrimidines. Their construction and degradation takes place in a progression of single steps, while different enzymes and cofactors are involved in the process. Beside degradation, there is also a form of reprocessing purine and pyrimidine nucleotides, d...

A requirement for carbon dioxide or bicarbonate has been demonstrated for the growth and survival of the Jensen, JA-1, and JA-2 sarcomas in vitro. When the cells were grown in the presenee of C140~, isotope was isolated in incorporated aspartic acid, glutamic acid, and proline as well as in the purines and pyrimidines. Although the relative specific activity of the purines and thymine was appro...