Protein synthesis studies in skeletal muscle of aging rats. II. In vitro studies with 0.5M potassium chloride washed polyribosomes

• Published in: Journal of gerontology (Kirkwood) Vol. 39; no. 4; p. 392
• Main Authors: Burini, R C, Pluskal, M G, Wei, I, Young, V R
• Format: Journal Article
• Language: English
• Published: United States 01.07.1984
• Subjects: Aging; Amino Acids - metabolism; Animals; Cell-Free System; In Vitro Techniques; Male; Polyribosomes - metabolism; Potassium Chloride - pharmacology; Protein Biosynthesis; Rats; Rats, Inbred Strains
• ISSN: 0022-1422
• DOI: 10.1093/geronj/39.4.392

To investigate further the age-related reduction in muscle protein synthesis activity found previously using a crude polyribosome/pH 5 system (Pluskal et al., 1984), a 0.5M KCl washing procedure was utilized to remove the nonribosomal factors from polyribosomes isolated from male Sprague-Dawley rats in the following age groups: young (1 to 2 months), mature (12 months), and aged (22 to 24 months). Using a common source of enriched elongation factor fraction from young animals, it was not possible to demonstrate any significant difference (p greater than .05) in protein synthesis between the 0.5M KCl-washed polyribosomes isolated from the various age groups. Using a cell-free system containing young salt washed polyribosomes stimulated by the addition of 0.5M KCl-wash fractions, however, it was shown that the mature and aged salt-wash fractions were less (p less than .05) active than material from young animals. Thus, the observed decline in protein synthesis efficiency during aging may be attributed to a reduced capacity to promote initiation/elongation by the nonribosomal salt wash fractions of muscle polyribosomes.