7; 410762 - . (MN2/9}), Interdiscipl. Topics Geront., vol. 9, pp. 209-218 (Karger, Basel 1976) . . \ R.A. Popp, E.G. Batuirr, G.P. Hirscu, and R. A. CONRAD nn o Q oO z Cc 9 9 m p SN rm 9 2 [8 Ss S72/ —-eC8 Transcription and translation of the genetic message in cells are not infinitely precise and OrGEL [9] has suggested that errors in protein synthesis may become more numerous with age and that the accumulation of'errorcontaining protcins could contribute to the ageing process. Indeed, Lewis and TarRANT [5] have presented evidence for the accumulation ofaltered, inactive lactic dehydrogenase molecules in cultures of humanfibroblasts prior 3 \ Yk. 6 Introduction a mo Q a4 ° Biology Division, Oak Ridge National Laboratory, Oak Ridge, Tenn., and Brookhaven National Laboratory, Upton, N.Y. @ 4 Pray IA . Errors in Human Hemoglobin as a Function of Age S 5 from NICHHD). d *2 ans yopuog yavasoy JR2pI MLL 1 Research supported by the US Atomic Energy Commission under contract with Union Carbide Corporation and by Ageing Research Training grant (PHS grant HO 00296 g Aa0 WseT] jeuoneN woARIpool [4] have shownthat fructose-1,6-diphosphate aldolase in livers of old mice is similarly altered; the specific activity of aldolase in the livers of old mice is only half that in young mice. They suggested that the inactive molecules may contain errors of mistranslation which arose at an increased frequencyas the tissue culture cells and mice age. LOFTFIELD [6] and LorrrieLp and VANDERJAGT [7] have measured the frequency of substitution of one amino acid for another during the synthesis of egg albumin and rabbit hemoglobin. In the former study, valine or leucine was found to substitute for isoleucine at a frequency of about 3 per 10,000 residues; in the latter study where a better defined protein and better purification procedures were used, valine was found to substitute for isoleucine at two positions in rabbit hemoglobin at a frequency of 2-6 per [0,000 residues. YIOX Ma sy Ty ‘10;07) to the death of these established cell lines. Moreover, GERSHON and GERSHON