scholarly journals Nuclease activity in cell-free amino acid-incorporating systems from chicken liver

1968 ◽  
Vol 109 (2) ◽  
pp. 185-190 ◽  
Author(s):  
Jack G. Siler ◽  
Melvin Fried
Keyword(s):  
Amino Acid ◽  
Rat Liver ◽  
Liver Cell ◽  
Free Amino ◽  
Nuclease Activity ◽  
Chicken Liver ◽  
Lower Activity ◽  
Insoluble Material ◽  
Polyuridylic Acid ◽  
System 2

1. Comparative studies of the polyuridylic acid-directed phenylalanine-incorporating activity of cell-free systems derived from rat and chicken livers demonstrated markedly lower activity in the chicken liver system. 2. The chicken liver cell sap contained the factor(s) responsible for this lower activity. Ribosomes from chicken and rat performed equally well in the presence of rat liver cell sap. Chicken liver cell sap, when mixed with rat liver cell sap, caused an inhibition of incorporation of phenylalanine into acid-insoluble material. 3. Though ribosomal preparations and cell sap from both rat and chicken liver degraded polyuridylic acid to some extent, the chicken liver cell sap contained the largest amount of activity. 4. Rat liver cell sap inhibited the nuclease activities of ribosomal preparations, but no such nuclease inhibition could be demonstrated with chicken liver cell sap.

scholarly journals Polyribonucleotide synthesis by subfractions of microsomes from rat liver

1968 ◽  
Vol 109 (2) ◽  
pp. 229-238 ◽  
Author(s):  
N. M. Wilkie ◽  
R. M. S. Smellie
Keyword(s):  
Acetic Acid ◽  
Rat Liver ◽  
Transfer Rna ◽  
Light Fraction ◽  
Free Ribosome ◽  
Polyadenylic Acid ◽  
Insoluble Material ◽  
Polyuridylic Acid ◽  
Microsome Fraction

1. The microsome fraction of rat liver has been fractionated and the ability of the fractions to incorporate ribonucleotides into polyribonucleotides has been studied. Activity was found in the rough-surfaced vesicle (light) fraction and in the free-ribosome fraction and this latter activity has been examined. 2. The free-ribosome fraction contains ribosome monomers, dimers and trimers together with some higher oligomers and ferritin. In addition to catalysing the incorporation of ribonucleotides into acid-insoluble material it contains diesterase activity. It catalyses the incorporation of UMP from UTP, but not UDP, AMP from ATP and CMP from CTP into polyribonucleotide material, and for UTP the product appears to be a homopolymer not more than eight units long attached to the ends of primer polyribonucleotide strands. 3. The activity could not be removed from the free-ribosome fraction by washing or by isolation in the presence of ethylenediaminetetra-acetic acid. 4. Partially hydrolysed polyuridylic acid but not polyadenylic acid could serve as a primer for the incorporation of UMP, but some activity was always associated with an endogenous primer. 5. Analysis of RNA extracted from the free-ribosome fraction after incubation with [3H]UTP showed the presence of 28s, 18s, 5s and transfer RNA types, but no radioactivity was associated with any of these RNA fractions.

Total Free Amino Acid Levels in Adult and Senescent Rat Liver

Gerontology ◽  
1978 ◽  
Vol 24 (1) ◽  
pp. 32-36 ◽  
Author(s):  
R.L. Eichholz ◽  
D.E. Buetow
Keyword(s):  
Amino Acid ◽  
Free Amino Acid ◽  
Rat Liver ◽  
Free Amino ◽  
Total Free Amino Acid ◽  
Amino Acid Levels

scholarly journals Effect of cycloheximide on protein biosynthesis in rat liver

1966 ◽  
Vol 101 (3) ◽  
pp. 627-631 ◽  
Author(s):  
A Korner
Keyword(s):  
Amino Acid ◽  
Rat Liver ◽  
Mouse Liver ◽  
Species Differences ◽  
Protein Biosynthesis ◽  
Amino Acid Incorporation ◽  
Acid Incorporation ◽  
Polyuridylic Acid ◽  
Liver Ribosomes

1. The liver ribosomes of rats given cycloheximide by intraperitoneal injection incorporate less amino acid into protein than ribosomes from control rat liver when they are incubated in vitro with excess of Sephadex-treated cell sap. The effect is rapid, marked and persistent. 2. Cell sap from liver of cycloheximide-treated animals is inhibitory but the inhibition can be relieved almost entirely by treating the cell sap with Sephadex. No damage has been done to the cell-sap factors: it is suggested that the dissolved cycloheximide in the cell sap causes the inhibition. 3. Cycloheximide added in vitro inhibits amino acid incorporation into protein in the presence or absence of polyuridylic acid. The inhibition is lessened by addition of excess of cell sap but is not abolished. 4. The differences between these results and those obtained with mouse liver (Trakatellis, Montjar & Axelrod, 1965) might arise because of species differences in sensitivity to the drug.

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