Metabolism of Pyrimidines and Purines

Purine and Pyrimidine Nucleotide Synthesis and Metabolism

“…Detailed descriptions of the early research in this area as well as additional references to studies of these pathways in plants other than Arabidopsis can be found in Takahashi and Suzuki (1977), Wasternack (1982), Rose and Last (1994) and Crozier and Ashihara (1999).…”

Purification and Characterization of Phosphoribosylpyrophosphate Synthetase from Rubber Tree Latex

“…Moreover, this compound is an essential substrate for severa1 metabolic pathways, including purine, pyrimidine, and nicotinamide nucleotide de novo synthesis and salvage pathways, but also for Trp and His biosynthesis (Wasternack, 1982). The essential function of PRPP has already been highlighted in the animal (Becker et al, 1979) and plant (Hirose and Ashihara, 1983;Le Floc'h, 1984;Dancer and Rees, 1989) kingdoms.…”

Nucleotide Metabolism

“…However, no such complex has thus far been detected in plants (see Moffatt and Ashihara, 2002). Although there are two different types of carbamoyl phosphate synthetases that provide substrates for pyrimidine and arginine biosynthesis in most eukaryotes, including mammals, the first complete plant genome sequence (the Arabidopsis Genome Initiative 2000) together with biochemical studies (Wasternack, 1982) reveal that higher plants possess only a single form of CPSase like E. coli that supplies carbamoylphosphate to both the pyrimidine and the arginine pathway. Plant CPSase consists of two subunits.…”

“…Some of the pyrimidine bases and nucleosides produced as degradation products of nucleotide and nucleic acids are re-utilised for generation of pyrimidine nucleotides (see Ross, 1981;Wasternack, 1982;Wagner and Backer, 1992). Uracil, one of the pyrimidine bases, is salvaged by the PRPP-dependent uracil phosphoribosyltransferase (UPRT).…”

“…Purine nucleosides and nucleobases arise from the intercellular breakdown of unstable RNA and nucleotides, and in some cases, originate from exogenous sources as catabolic products of nucleic acids and nucleotides in decaying cells (Wasternack, 1982;Bray, 1983). Adenosine released from hydrolysis of S-adenosyl-L-homocysteine in the S-adenosyl-L-methionine cycle, and adenine released in the methionine cycle of ethylene synthesis, are also utilised as substrates for purine salvage (Wasternack, 1982;Ashihara and Crozier, 1999;Crozier et al, 2000;Moffatt and Ashihara, 2002). Several enzymes involved in purine salvage have been found in higher plants.…”