Effect of acclimation temperature on the elongation step of protein synthesis in different organs of rainbow trout |
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Authors: | Enno Simon |
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Institution: | (1) Department of Zoophysiology, University of Kiel, Olshausenstraße 40-60, D-2300 Kiel, Germany |
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Abstract: | Summary Cytosolic extracts of liver, kidney, spleen, gill, red and white muscle from rainbow trout acclimated to 4 and 17°C, respectively, have been investigated in vitro with respect to their enzymic activity in stimulating the growth of nascent peptide chains (labelled polyphenylalanine) at assay temperatures from 5 to 25°C using polyuracil as messenger RNA. The elongation step of protein synthesis is characterized by aQ
10 value of about 2.4 (range 10–25°C) in all organs from both, 4 and 17°C acclimated fish.Except for the red muscle, the organs of cold acclimated trout, however, exhibit significantly higher specific elongation rates (mol phenylalanine polymerized/(g wet weight·h)) at any experimental temperature than those of warm acclimated fish. This increase of the elongation rates varies between the organs and ranges from +29% (liver) to +60% in the gill. The specific acylation rate (mol phenylalanyl-tRNA formed/(g wet weight·h)) surpasses the specific elongation rate by a factor of at least 8.5. Moreover, the specific acylation rate per mg protein is independent of acclimation temperature.It is concluded that the increased specific elongation rates in 4°C acclimated trout are not due to altered pool sizes of the precursor phenylalanyl-tRNA, but reflect an effective enhancement of enzymic elongation factor activities.In accordance with data taken from literature, this finding suggests a compensatory enhancement of in vivo protein synthesis to occur in trout during cold acclimation.Abbreviations
E
a
apparent activation energy
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EF
elongation factor
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HEPES
N-2-hydroxyethylpiperazine-N -2-ethane sulfonic acid
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PHE
phenylalanine
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PHE-tRNA
phenylalanyl transfer ribonucleic acid
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POLY (U)
poly-uracil
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Q
10
van't Hoff's temperature coefficient
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T
accl
acclimation temperature
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T
exp
experimental temperature
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TRITON X-100
octylphenol-polyethylene-glycolether |
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Keywords: | |
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