Aspartic acid racemization on aging

Leon Trotsky said, “old age is the most unexpected of all the things that can happen to a man”,1 but it seems difficult to believe as the process of growing old is accompanied by a plethora of physical signs, which can be easily recognised. The progressive appearance of wrinkles and grey hair as well as changes in height, vision or hearing are the detectable consequences of the cellular and molecular changes taking place in our organism as years go by. Different mechanisms are considered hallmarks of aging like genomic instability, stem cell exhaustion or telomere attrition (Lopez-Otin et al. 2013). Among them, proteostasis is defined as a state of dynamic equilibrium in which protein stability and functionality is preserved, all thanks to a complex network of processes designed to control the fate of a protein from synthesis to degradation (Balch et al. 2008). Unfortunately, these mechanisms cannot completely avoid the accumulation of unwanted protein products and it is becoming clear that proteostasis malfunction has a key role in aging and its related disorders (Taylor and Dillin 2011).