In an investigation of transamination reactions between pyridoxal and amino acids at 100” (2) serine was found to behave anomalously, apparently being deaminated to pyruvic acid with little change in pyridoxal concentration. Although serine is known to be deaminated by hot concentrated alkalies (3) and acids (4), such a non-enzymatic reaction in the pH range near neutrality has not been reporte...

Oxetanocin A (OXT-A, 1), which was isolated as a natural product, is a nucleoside analogue with adenine as base moiety as similar as DDAand araA. It shows antiviral activities against HIV, human cytomegalovirus (HCMV), and herpes simplex virus type 1 and 2 (HSV-1,2).7) Its usefulness is, however, limited by several drawbacks. A major drawback of OXT-Ais a short half-life time in plasma partly d...

RNA editing by adenosine deamination is a process used to diversify the proteome. The expression of ADARs, the editing enzymes, is ubiquitous among true metazoans, and so adenosine deamination is thought to be universal. By changing codons at the level of mRNA, protein function can be altered, perhaps in response to physiological demand. Although the number of editing sites identified in recent...

Deamination of the oncogenic 1-methylguanine 3-oxide occurs to a significant extent in rats to yield 3-hydroxy-1-methylxanthine and its metabolites. When 3-hydroxy-1-methylxanthine is administered, 1-methyl-8-methylthioxanthine can be recovered from urine and released from hepatic protein. No 1-methyl-8-methylthioguanine was detected in urine or bound to protein. There is no evidence of signifi...

The heat-induced conversion of 5-methylcytosine (m5C) residues to thymine residues and of cytosine to uracil residues in single-stranded DNA was studied. The calculated rates for deamination at 37 degrees C and pH 7.4 were approximately 9.5 X 10(-10) and 2.1 X 10(-10) sec-1, respectively. N4-Methyldeoxycytidine, which is in the DNA of certain thermophilic bacteria, was more heat-resistant than ...

Cytidine deaminase (cytidine aminohydrolase, EC 3.5.4.5) has been purified approximately 160-fold from extracts of Escherichia coli B. The enzyme shows constant activity between pH 6 and 11. No significant change in rate is observed when DzO replaces water as the solvent. In addition to the deamination of cytidine, the purified deaminase catalyzes slow hydrolysis of N4-methylcytidine. The enzym...

A variety of nucleoside analogs have shown carcinostatic activity. In some instances they are relatively rapidly excreted. In others they are relatively rapidly inactivated in vivo by catabolic enzymes. In both cases it appeared desirable to have nucleoside derivatives that would act as depot forms of the nucleoside analogs and would be converted in vivo to the respective nucleoside analog. Gis...