Sgarrella F, Poddie F P, Meloni M A, Sciola L, Pippia P, Tozzi M G
Dipartimento di Scienze del Farmaco, Università di Sassari, Italy.
Comp Biochem Physiol B Biochem Mol Biol. 1997 Jun;117(2):253-7. doi: 10.1016/s0305-0491(96)00325-2.
In bacteria, the addition of (deoxy)nucleosides or (deoxy)ribose to the growth medium causes induction of enzymes involved in their catabolism, leading to the utilisation of the pentose moiety as carbon and energy source. In this respect, deoxyriboaldolase appears the key enzyme, allowing the utilisation of deoxyribose 5-P through glycolysis. We observed that not only deoxynucleosides, but also DNA added to the growth medium of Bacillus cereus induced deoxyriboaldolase; furthermore, the switch of the culture from aerobic to anaerobic conditions caused a further increase in enzyme activity, leading to a more efficient channelling of deoxyribose 5-P into glycolysis, probably as a response to the low energy yield of the sugar fermentation. In eukaryotes, the catabolism of (deoxy)nucleosides is well known. However, the research in this field has been mainly devoted to the salvage of the bases formed by the action of nucleoside phosphorylases, whereas the metabolic fate of the sugar moiety has been largely neglected. Our results indicate that the deoxyriboaldolase activity is present in the liver of several vertebrates and in a number of cell lines. We discuss our observations looking at the nucleic acids not only as informational molecules, but also as a not negligible source of readily usable phosphorylated sugar.
在细菌中，向生长培养基中添加（脱氧）核苷或（脱氧）核糖会诱导参与其分解代谢的酶的产生，从而导致戊糖部分被用作碳源和能源。在这方面，脱氧核糖醛缩酶似乎是关键酶，它能使5-磷酸脱氧核糖通过糖酵解被利用。我们观察到，不仅脱氧核苷，而且添加到蜡状芽孢杆菌生长培养基中的DNA也能诱导脱氧核糖醛缩酶的产生；此外，将培养条件从需氧改为厌氧会导致酶活性进一步增加，从而使5-磷酸脱氧核糖更有效地进入糖酵解途径，这可能是对糖发酵低能量产率的一种响应。在真核生物中，（脱氧）核苷的分解代谢是众所周知的。然而，该领域的研究主要致力于由核苷磷酸化酶作用形成的碱基的补救，而糖部分的代谢命运在很大程度上被忽视了。我们的结果表明，脱氧核糖醛缩酶活性存在于几种脊椎动物的肝脏和许多细胞系中。我们不仅将核酸视为信息分子，而且将其视为一种不可忽视的易于利用的磷酸化糖来源，在此基础上讨论我们的观察结果。
