The diguanosine nucleotides: do they exist in aquatic fungi?

Warner, Alden H.; Thomas, D. des S.; Shridhar, Vijayalakshmi; McCurdy, Howard D.

doi:10.1139/o77-124

Cited by 5 publications

(1 citation statement)

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“…guanosine(5')tetraphospho(51)guanosine] have been found in considerable quantities as naturally occurring nucleotides in the brine shrimp (Finamore & Warner, 1963;Warner & Finamore, 1965) and in Daphnia magnum (Oikawa & Smith, 1966). A range of aquatic fungi also possess different, though as yet incompletely identified, polyphosphate compounds (Warner et al, 1977;Goh & Le John, 1977). The precise function of these nucleotides is not known, but it is possible that they serve as a stable energy reservoir, being converted into ATP with conservation of pyrophosphate bonds (Clegg et al, 1967), and they appear to act as a purine store during embryogenesis in Artemia salina, when purine-synthetic pathways are absent (Warner & McClean, 1968).…”

Section: Fig 5 Tissue Contents Ofadpandatp In Theperfusedheartmentioning

confidence: 99%

Systematic variations in the content of the purine nucleotides in the steady-state perfused rat heart. Evidence for the existence of controlled storage and release of adenine nucleotides

Bates

Perrett

Mowbray

1978

Biochemical Journal

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1. The contents of the major purine nucleotides in the isolated non-working perfused rat heart varied systematically during 80min of perfusion. In particular the amounts of ATP, ADP, GTP, cyclic AMP and cyclic GMP in the well-oxygenated myocardium showed changes ranging from 25 to 60% of the mean concentrations. The apparent periodicity was about 30min for some and about 60min for other nucleotides. 2. These data are in contrast with measurements of parameters reflecting heart performance, which remained constant over this period of perfusion. 3. The ATP/ADP ratio, the cyclic AMP content, the GTP content and the GTP/GDP ratio in the tissue bore a constant relationship to one another, and all showed the same temporal variation. 4. Increasing the energy demand on the heart by administration of bovine somatotropin (1mug/ml) tended to damp the variations, and generally lower the content of all the nucleotides. 5. The total extractable adenine nucleotide pool also showed systematic temporal variations of as much as 1.3mumol/g wet wt. of tissue within 10min. 6. These variations could not be accounted for as inter-conversion with adenosine, other purine nucleotides, nucleosides or purine-degradation products either in the tissue or in the perfusion medium. No evidence was found in this preparation of the purine nucleotide oscillations described by Lowenstein and his co-workers [see Tornheim & Lowenstein (1975) J. Biol. Chem.250, 6304-6314]. 7. Further, the pool size increases cannot be satisfactorily explained by either synthesis de novo or the breakdown of any purine macromolecular species in the cell. Thus it is suggested that an unsuspected substantial storage form of purine nucleotide may exist in heart.

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