Biochemical research on oogenesis. Aminoacyl tRNA turns over in the 42-S particles of Xenopus laevis oocytes, but its ester bond is protected against hydrolysis.
The ester bond aminoacyl tRNA is protected against hydrolysis in the 42-S particles (thesaurisomes) present in Xenopus laevis previtellogenic oocytes. Deacylation of tRNA is very slow in vitro, unless ATP is present. ATP causes a partial turnover of aminoacyl tRNA in vitro, with no detectable decrease in the overall aminoacylation level of tRNA, which remains close to 100%. tRNA in the particles turns over rapidly in vivo. Since the ester bond of aminoacyl tRNA is stabilized inside the 42-S particles, this turnover cannot be a consequence of spontaneous deacylation of tRNA, followed by reacylation by the aminoacyl-tRNA synthetases associated with the particles. We rather consider this turnover as reflecting a true metabolic activity of the particles, and a direct or indirect involvement of these particles in the oocyte's protein-synthesizing system.
D000255:Adenosine Triphosphate / Q000502:physiology; D000818:Animals; D002499:Centrifugation, Density Gradient; D004527:Egg Proteins / Q000096:biosynthesis; D004952:Esters / Q000378:metabolism; D005260:Female; D006868:Hydrolysis; D007700:Kinetics; D008433:Mathematics; D009865:Oocytes / Q000378:metabolism*; D011485:Protein Binding; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism*; D014982:Xenopus laevis
D004527:Egg Proteins; D004952:Esters; D012346:RNA, Transfer, Amino Acyl; D000255:Adenosine Triphosphate