Putrescine aminotransferase

Aminopeptidase, cytosol Aminopeptidase, leucine Aminopropyltransferase, putrescine Aminotransferase Aminotransferase, alanine Aminotransferase, aspartate Aminotransferase, glutamate-glyoxylate Aminotransferase, ornithine-keto acid Aminotransferase, serine-glyoxylate Ammonia... 

The urea so formed is distributed throughout the body water and excreted. The renal clearance of urea is less than the glomerular filtration rate because of passive tubular back-diffusion. Diffusion of urea in the intestine leads to formation of ammonia, which enters the portal blood and is converted to urea in liver. Reentry of ornithine into mitochondria initiates the next revolution of the urea cycle. Ornithine can be converted to glutamate-y-semialdehyde (which is in equilibrium with its cyclic form A -pyrroline-5-carboxylate) by ornithine aminotransferase and de-carboxylated to putrescine by ornithine decarboxylase. Ornithine is also produced in the arginine-glycine trans-amidinase reaction. 

Decarboxylation of ornithine to putrescine by ornithine decarboxylase serves as a source of the polyamines spermidine and spermine. Ornithinemia results from deficiency of ornithine aminotransferase or ornithine... 

Keywords Aminotransferase Putrescine utilization pathway Spermidine acetyltransferase Transporter y-Aminobutyric acid y-Glutamyl intermediate y-Glutamylation... 

Two pathways, the aminotransferase pathway and the putrescine utilization pathway (the Puu pathway) (see Fig. 4.1), are responsible for the cataboUsm of putrescine to yield nitrogen and carbon sources for growth. 

In P. aeruginosa PAOl, the first enzyme of the aminotransferase pathway was reported as putrescine-pyruvate aminotransferase, which generates y-aminobutyraldehyde and L-alanine (Lu et al. 2002 Chou et al. 2013). 

Putrescine transporter Y-Glutamyl- putrescine synthetase y-Qiutamyi- Repressor QABA hydroiese 1 1 y-Giutamyi- y-aminobutyr- aidehyde dehydrogenase y-Giutamyi- putrescine oxidase GABA aminotransferase... 

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