Biosynthesis of neopterin, sepiapterin, and biopterin in rat and human ocular tissues.
Neopterin, sepiapterin, and biopterin synthesis by lens, retina, and ciliary body-iris of rat and human indicates pteridine formation from their precursor, GTP. The pteridine biosynthesis was higher in the retina (neopterin 422 +/- 27, 260 +/- 24; sepiapterin 135 +/- 12, 118 +/- 14; biopterin 76 +/- 10, 68 +/- 8 nanomoles/g soluble protein/hr, in rat and human, respectively) than in the ciliary body-iris and lens. The light-sensitive pteridines may protect eye tissues against the effects of sunlight in addition to their role in the hydroxylation of aromatic amino acids.
D000818:Animals; D001708:Biopterins / Q000031:analogs & derivatives / Q000096:biosynthesis*; D002924:Ciliary Body / Q000378:metabolism; D005123:Eye / Q000378:metabolism*; D006801:Humans; D007498:Iris / Q000378:metabolism; D007908:Lens, Crystalline / Q000378:metabolism; D019798:Neopterin; D011621:Pteridines / Q000096:biosynthesis*; D011622:Pterins; D051381:Rats; D012160:Retina / Q000378:metabolism
D011621:Pteridines; D011622:Pterins; D001708:Biopterins; D019798:Neopterin; C016727:sepiapterin