The central dogma describes the unidirectional flow of genetic information from DNA to proteins, leading to an underappreciation of the potential for the information contained in proteomes (the full set of proteins in an organism) to reflect broader biological processes such as lifespan. Here, this is addressed by examining how the size and composition of 276 proteomes from four vertebrate classes are related to lifespan. After accounting for the relationship between body weight and lifespan, lifespan is negatively correlated with proteome size in birds and, to a weaker extent, in fish, and positively correlated with lifespan in mammals. Proteome composition varies amongst the four vertebrate classes, but there is no evidence that any specific amino acid correlated with lifespan. The findings in relation to the role of dietary amino acid restriction are discussed on lifespan extension and raise questions about evolutionary and structural forces shaping proteome composition across species.