A methyl group ( CH 3 ) binds to an arginine on the histone protein, which can induce transcription of the DNA . When PAD converts arginine to citrulline, it no longer induces transcription.
42.
Non-proteinogenic amino acids often occur as intermediates in the metabolic pathways for standard amino acids for example, ornithine and citrulline occur in the urea cycle, part of amino acid catabolism ( see below ).
43.
With urine chromatography, increased levels of neutral amino acids ( e . g ., glutamine, valine, phenylalanine, leucine, asparagine, citrulline, isoleucine, threonine, alanine, serine, histidine, tyrosine, tryptophan ) and indican are found in the urine.
44.
Oxidation of L-Arg to L-citrulline occurs via two successive monooxygenation reactions producing " N " ?-hydroxy-L-arginine ( NOHLA ) as an intermediate . 2 mol of O 2 and 1.5 mol of NADPH are consumed per mole of NO formed.
45.
In ASS from " T . thermophilus ", " E . coli ", and " H . sapiens ", citrulline and aspartate are tightly bound in the active site by interactions with serine and arginine residues; interactions of the substrates with other residues in the active site vary by species.
46.
On a whole-body basis, synthesis of arginine occurs principally via the intestinal renal axis, wherein epithelial cells of the small intestine, which produce citrulline primarily from glutamine and glutamate, collaborate with the proximal tubule cells of the kidney, which extract citrulline from the circulation and convert it to arginine, which is returned to the circulation.
47.
On a whole-body basis, synthesis of arginine occurs principally via the intestinal renal axis, wherein epithelial cells of the small intestine, which produce citrulline primarily from glutamine and glutamate, collaborate with the proximal tubule cells of the kidney, which extract citrulline from the circulation and convert it to arginine, which is returned to the circulation.
48.
Synthesis of arginine from citrulline also occurs at a low level in many other cells, and cellular capacity for arginine synthesis can be markedly increased under circumstances that also induce iNOS . Thus, citrulline, a coproduct of the NOS-catalyzed reaction, can be recycled to arginine in a pathway known as the citrulline-NO or arginine-citrulline pathway.
49.
Synthesis of arginine from citrulline also occurs at a low level in many other cells, and cellular capacity for arginine synthesis can be markedly increased under circumstances that also induce iNOS . Thus, citrulline, a coproduct of the NOS-catalyzed reaction, can be recycled to arginine in a pathway known as the citrulline-NO or arginine-citrulline pathway.
50.
Synthesis of arginine from citrulline also occurs at a low level in many other cells, and cellular capacity for arginine synthesis can be markedly increased under circumstances that also induce iNOS . Thus, citrulline, a coproduct of the NOS-catalyzed reaction, can be recycled to arginine in a pathway known as the citrulline-NO or arginine-citrulline pathway.
