Reverter-Branchat Gemma, Cabiscol Elisa, Tamarit Jordi, Sorolla M Alba, Ángeles de la Torre M, Ros Joaquim
Bioquímica de l'Estrès Oxidatiu, Departament de Ciències Mèdiques Bàsiques, IRBLleida, Universitat de Lleida, 25008 Lleida, Spain.
Microbiology (Reading). 2007 Nov;153(Pt 11):3667-3676. doi: 10.1099/mic.0.2007/009340-0.
Alcohol dehydrogenase 1 (Adh1)p catalyses the conversion of acetaldehyde to ethanol, regenerating NAD+. In Saccharomyces cerevisiae, Adh1p is oxidatively modified during ageing and, consequently, its activity becomes reduced. To analyse whether maintaining this activity is advantageous for the cell, a yeast strain with an extra copy of the ADH1 gene (2xADH1) was constructed, and the effects on chronological and replicative ageing were analysed. The strain showed increased survival in stationary phase (chronological ageing) due to induction of antioxidant enzymes such as catalase and superoxide dismutases. In addition, 2xADH1 cells displayed an increased activity of silent information regulator 2 (Sir2)p, an NAD+-dependent histone deacetylase, due to a higher NAD+/NADH ratio. As a consequence, a 30% extension in replicative life span was observed. Taken together, these results suggest that the maintenance of enzymes that participate in NAD+/NADH balancing is important to chronological and replicative life-span parameters.
乙醇脱氢酶1（Adh1）p催化乙醛转化为乙醇，使NAD +再生。在酿酒酵母中，Adh1p在衰老过程中会发生氧化修饰，因此其活性会降低。为了分析维持这种活性对细胞是否有利，构建了一个带有额外ADH1基因拷贝（2xADH1）的酵母菌株，并分析了其对时序衰老和复制性衰老的影响。由于过氧化氢酶和超氧化物歧化酶等抗氧化酶的诱导，该菌株在稳定期（时序衰老）的存活率有所提高。此外，由于较高的NAD + / NADH比率，2xADH1细胞中沉默信息调节因子2（Sir2）p的活性增加。结果，观察到复制寿命延长了30％。综上所述，这些结果表明，参与NAD + / NADH平衡的酶的维持对时序和复制寿命参数很重要。
