Total aminoacyl-transfer RNA pool is greater in liver than muscle in rabbits.
Transfer RNA (tRNA)-charged amino acids are direct precursors of protein synthesis. Therefore, the amount and profile of amino acids in the aminoacyl-tRNA pool may be closely related to the rate of protein synthesis in the tissue. This study was designed to compare the aminoacyl-tRNA pools in liver and muscle, 2 distinct tissues with different rates of protein synthesis. Liver and muscle samples were taken from 6 rabbits and aminoacyl-tRNA was isolated with sequential acid-phenol:chloroform extraction, followed by total RNA and tRNA purification. Amino acids in the aminoacyl-tRNA pool were measured by HPLC after deacylation. Liver contained 3.4 times more tRNA than muscle (585 +/- 120 vs. 132 +/- 11 microg of tRNA/g of tissue; P < 0.001). Overall tRNA charging was also greater in liver (14.22 +/- 4.42 nmol of amino acids/mg of tRNA) than in muscle (7.00 +/- 1.76 nmol of amino acids/mg of tRNA) (P < 0.05). The greater availability and charging efficiency of tRNA in liver as compared with muscle may influence the extent to which amino acid precursor availability regulates protein synthesis in these 2 tissues.
Wolfe
Robert R
RR
Donald W. Reynolds Institute on Aging, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA. rwolfe2@uams.edu
Song
Juquan
J
Sun
Jinchun
J
Zhang
Xiao-jun
XJ
D000596:Amino Acids / Q000302:isolation & purification / Q000378:metabolism; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D008099:Liver / Q000502:physiology*; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D011506:Proteins / Q000302:isolation & purification / Q000378:metabolism; D012313:RNA / Q000302:isolation & purification / Q000378:metabolism; D012343:RNA, Transfer / Q000302:isolation & purification / Q000378:metabolism; D012346:RNA, Transfer, Amino Acyl / Q000302:isolation & purification / Q000378:metabolism*; D011817:Rabbits
D000596:Amino Acids; D011506:Proteins; D012346:RNA, Transfer, Amino Acyl; D012313:RNA; D012343:RNA, Transfer