title: Purine salvage as a metabolite and energy saving mechanism in the ocular lens.
abstract: The ocular lens is an organ which depends mainly on anaerobic processes to obtain the metabolic energy required for the maintenance of its physiological functions. In these circumstances, the purine salvage pathway enzymes, by using preformed purine rings, and allowing the utilization of the activated ribose moiety of nucleosides, might be of relevance as an energy saving device. In this paper we show that the calf lens possesses many enzymes of the purine salvage pathway, with a particularly high specific activity of purine nucleoside phosphorylase (EC 2.4.2.1), and that the isolated lens epithelium can actively convert adenine and adenosine into adenine nucleotides. In addition, as in bacteria and red blood cells, inosine and adenosine in the lens, acting as ribose donors, exert a profound effect on the process of adenine conversion into ATP.
authors.affiliation: Dipartimento di Fisiologia e Biochimica, Università di Pisa, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Cappiello
authors.forename: D
authors.initials: D
authors.lastname: Barsacchi
authors.forename: A
authors.initials: A
authors.lastname: Del Corso
authors.forename: M G
authors.initials: MG
authors.lastname: Tozzi
authors.forename: M
authors.initials: M
authors.lastname: Camici
authors.forename: U
authors.initials: U
authors.lastname: Mura
authors.forename: P L
authors.initials: PL
authors.lastname: Ipata
mesh_terms: D000225:Adenine / Q000378:metabolism; D000241:Adenosine / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000096:biosynthesis*; D000818:Animals; D002417:Cattle; D004734:Energy Metabolism; D004848:Epithelium / Q000378:metabolism; D007288:Inosine / Q000378:metabolism; D007903:Lens Capsule, Crystalline / Q000378:metabolism*; D008297:Male; D010088:Oxidoreductases / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D014166:Transferases / Q000378:metabolism
chemical_list: D007288:Inosine; D000255:Adenosine Triphosphate; D010088:Oxidoreductases; D014166:Transferases; D000225:Adenine; D000241:Adenosine