Comparison of cell-free protein synthesis by different regions of chicken brain

Regeneration and protein synthesis in the spinal cord: the influence of ACTH-like peptides on cell-free protein synthesis

To measure protein synthesis at the level of the cell bodies of motoneurons of the sciatic nerve, anterior horns were punched out of the spinal cord using microdissection techniques and a cell-free system was prepared. Injections of ACTH1-16 and ACTH4-10 were shown to enhance protein synthesis in the cell-free system, 1.5 h after treatment. Neither crush lesion of the sciatic nerve nor systemic treatment with ACTH4-10 produced clear changes in overall protein synthesis. Thus, the increase in overall protein synthesis by acute treatment with ACTH-like peptides cannot explain the previously reported stimulation of axonal regeneration after nerve crush.

Biphasic modulation by ACTH-like peptides of protein synthesis in a cell-free system from rat brain

Brain protein synthesis in a cell-free system was stimulated by 10(-8) M-ACTH1-24. This stimulatory effect was completely inhibited by aurintricarboxylic acid (ATA), an inhibitor of reinitiation of new peptide chains. The N-terminal peptide sequence 4-10 exerted a biphasic modulation of cell-free protein synthesis, i.e., a stimulation at low concentrations (10(-8) and 10(-10) M) and an inhibition at a high concentration (10(-4) M). The D-isomer, ACTH4-10-7-D-phe, also showed a biphasic modulation that, however, was in a direction opposite to that shown by ACTH4-10-7-L-phe at 10(-8) M and 10(-4) M.

Cell-free protein synthesis by kidney from the aging female Fischer F344 rat

This is the first report to describe and characterize a cell-free protein synthesis system derived from kidney tissue. The optimum conditions for [3H]-valine incorporation into protein by the post-mitochondrial supernatant from whole kidneys were found to be: pH 6.9, 7.5 mM MgCl2, 150 mM KCl, 10 mM ATP, and 2 mM GTP. The cell-free protein-synthetising activities of kidneys isolated from 4.5-, 7.5-, 22-, and 31-month-old female Fischer F344 rats were measured using the post-mitochondrial supernatant. A 73-87% decrease in cell-free protein synthesis was observed between 4.5 and 31 months of age. Both the cell sap and microsomal fractions of the kidney post-mitochondrial supernatant from old rats were less active in protein synthesis than these fractions from the kidneys of young rats. No age-related change in the activity of RNAase in the kidney post-mitochondrial supernatant was observed. Kidney ribosomes stripped of endogenous mRNA were found to be active in poly(uridylic acid)-directed polyphenylalanine synthesis. The effect of aging on the fidelity of translation was determined by measuring poly(uridylic acid)-directed [14C]-phenylalanine and [3H]leucine incorporation by kidney ribosomes isolated from rats of various ages. No age-related change in the fidelity of poly(uridylic acid) translation by kidney ribosomes was observed.