scholarly journals Increased degradation rates of protein synthesized in hepatoma cells in the presence of amino acid analogues

1975 ◽  
Vol 146 (3) ◽  
pp. 595-600 ◽  
Author(s):  
S E Knowles ◽  
J M Gunn ◽  
R W Hanson ◽  
F J Ballard
Keyword(s):  
Amino Acid ◽  
Cell Cultures ◽  
Incubation Medium ◽  
Hepatoma Cells ◽  
Cell Protein ◽  
Chase Period ◽  
Separate Cell ◽  
Degradation Rates ◽  
Amino Acid Analogues

1. Reuber H35 hepatoma cells incorporate the arginine analogue canavanine into cell protein when arginine is omitted from the incubation medium. 2. By labelling arginine-containing proteins with (14-C)leucine and then canavanine-containing proteins with (3-H)leucine in the same cells, it is possible to measure the degradation of both types of protein during a subsequent ‘chase’ period. With this technique it has been shown that canavanine-containing proteins are degraded at a rate severalfold greater than normal proteins. Comparable results were found when 6-fluorotryptophan was used as an analogue to tryptophan. 3. Control experiments in which the labelling order was reversed or where the animo acid and its analogue were incubated in separate cell cultures support the conclusion that abberrant proteins are rapidly degraded in vivo.

scholarly journals Properties of phosphoenolpyruvate carboxykinase (guanosine triphosphate) synthesized in hepatoma cells in the presence of amino acid analogues

1975 ◽  
Vol 146 (3) ◽  
pp. 585-593 ◽  
Author(s):  
S E Knowles ◽  
J M Gunn ◽  
L Reshef ◽  
R W Hanson ◽  
F J Ballard
Keyword(s):  
Amino Acid ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Hepatoma Cells ◽  
Dibutyryl Cyclic Amp ◽  
Enzyme Degradation ◽  
Amino Acid Analogues ◽  
Enzyme Molecules ◽  
Natural Amino Acids

1. Phosphoenolpyruvate carboxykinase (GTP) was induced by a combination of dibutyryl cyclic AMP, theophyline and dexamethasone in Reuber H35 hepatoma cells under conditions where an amino acid in the medium was replaced by an appropriate analogue. 2. With canavanine replacing arginine or with 5-fluorotryptophan or 6-fluorotryptophan replacing tryptophan the induced enzyme had a lower catalytic activity-relative to antibody reactivity. 3. These aberrant enzyme molecules were heat-labile in vitro. 4. Measurements of enzyme degradation in vivo indicated that the canavanine-containing enzyme and the 6-fluorotryptophan-containing enzyme were degraded more rapidly than the enzyme containing all natural amino acids.

Site Specific Incorporation of Amino Acid Analogues into Proteins In Vivo

2000 ◽  
Author(s):  
Anne K. Kowal ◽  
Caroline Kohrer ◽  
Uttam L. RajBhandary
Keyword(s):  
Amino Acid ◽  
Site Specific ◽  
Amino Acid Analogues

scholarly journals KINETICS OF AMINO ACID INCORPORATION INTO SERUM PROTEINS

1955 ◽  
Vol 38 (3) ◽  
pp. 283-293 ◽  
Author(s):  
H. Green ◽  
H. S. Anker
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Serum Protein ◽  
Transit Time ◽  
Serum Proteins ◽  
Amino Acid Incorporation ◽  
Acid Incorporation ◽  
Amino Acid Analogues ◽  
Kinetics Of

1. The effect of varying body temperature on the rate of amino acid incorporation into serum protein does not give support to the idea that the rate of this process is adjusted in vivo to restore those protein molecules destroyed by thermal denaturation. The experimentally observed Q10 was about 3.9. 2. When amino acids are injected into the blood of animals in a steady state of serum protein turnover, a period of time elapses before these amino acids can be found in the serum proteins. This has been called transit time. At a given temperature (31°) it is the same in rabbits, turtles, and Limulus (1 hour). In rabbits and turtles it has a Q10 of 3.2. It appears to be specifically related to the process of synthesis (or release) of serum proteins. 3. It was not possible to affect the transit time or the incorporation rate by the administration of amino acid analogues.

Effects of hypophysectomy and growth hormone on utilizable amino acid accumulation

1962 ◽  
Vol 203 (5) ◽  
pp. 933-938 ◽  
Author(s):  
C. A. Snipes ◽  
J. L. Kostyo
Keyword(s):  
Amino Acids ◽  
Growth Hormone ◽  
Amino Acid ◽  
Incubation Medium ◽  
Cell Water ◽  
Bicarbonate Buffer ◽  
Acid Accumulation ◽  
Hypophysectomized Rats ◽  
Amino Acid Accumulation

Hypophysectomy decreased the concentrations of alanine and histidine in the cell water of the rat diaphragm, but had no influence on the levels of these amino acids in plasma. The concentrations of alanine and histidine in the cell water did not vary appreciably from in vivo values, when "intact" diaphragms of either normal or hypophysectomized rats were incubated in Krebs bicarbonate buffer. Addition of l-alanine or l-histidine to the incubation medium resulted in the accumulation of these amino acids in the cell water of both normal and hypophysectomized rat diaphragms. However, muscles or hypophysectomized rats accumulated these amino acids to a lesser extent. When added to the incubation medium, bovine growth hormone stimulated the accumulation of l-alanine and l-histidine by diaphragms of hypophysectomized rats. Thus, these experiments suggest that growth hormone participates in the regulation of utilizable amino acid transport into muscle.

ISOALDEHYDEDIUREAS AS NONPROTEIN NITROGEN SOURCES FOR RUMINANT ANIMALS

1989 ◽  
Vol 69 (4) ◽  
pp. 989-998
Author(s):  
MARINA A. G. VON KEYSERLINGK ◽  
G. W. MATHISON
Keyword(s):  
Experimental Design ◽  
Incubation Medium ◽  
Rumen Fluid ◽  
Nitrogen Sources ◽  
Isovaleric Acid ◽  
Nonprotein Nitrogen ◽  
Degradation Rates ◽  
Ruminant Animals

In experiments designed to evaluate isovaleridenediurea (IVDU; butanal, 3-methyl-di-urea) as a nonprotein nitrogen supplement for ruminant animals IVDU and isobutylidenediurea (IBDU; propanal, 2-methyl-di-urea) were compared to urea. Ammonia concentrations were increased (P < 0.05) by 2–5 mM when IBDU or IVDU were added to an in vitro incubation medium in comparison with up to 24 mM when equal amount of urea nitrogen was used. Isobutyric and isovaleric acid concentrations in the incubation medium were higher (P < 0.05) when IBDU and IVDU, respectively, were present. In an in vivo experiment, ammonia concentrations were reduced (P < 0.05) from 7.0 to 4.7 mM at 0.5 h after feeding when a mixture of 6 g IBDU and 6 g IVDU was substituted for 6.8 g urea in the diet of four sheep fed 1200 g hay and 100 g concentrate daily in a crossover experimental design. No differences (P > 0.05) in isobutyric or isovaleric acid concentrations in the rumen fluid were observed between treatments. Apparent digestibilities were not influenced by diet. It was concluded that although IVDU and IBDU had potential as nonprotein nitrogen supplements, degradation rates of both compounds were low and excessive amounts of the compounds may escape from the rumen undegraded. Key words: Sheep, isobutylidenediurea, isovaleridenediurea, nonprotein nitrogen supplements, in vitro, in vivo

scholarly journals Cysteine Restriction in Murine L929 Fibroblasts as an Alternative Strategy to Methionine Restriction in Cancer Therapy

2021 ◽  
Vol 22 (21) ◽  
pp. 11630
Author(s):  
Werner Schmitz ◽  
Elena Ries ◽  
Corinna Koderer ◽  
Maximilian Friedrich Völter ◽  
Anna Chiara Wünsch ◽  
...  
Keyword(s):  
Amino Acid ◽  
Turnover Rate ◽  
Low Energy ◽  
Single Amino Acid ◽  
Proliferation Inhibition ◽  
Murine Cell Line ◽  
Methionine Restriction ◽  
Cysteine Synthesis ◽  
Amino Acid Analogues

Methionine restriction (MetR) is an efficient method of amino acid restriction (AR) in cells and organisms that induces low energy metabolism (LEM) similar to caloric restriction (CR). The implementation of MetR as a therapy for cancer or other diseases is not simple since the elimination of a single amino acid in the diet is difficult. However, the in vivo turnover rate of cysteine is usually higher than the rate of intake through food. For this reason, every cell can enzymatically synthesize cysteine from methionine, which enables the use of specific enzymatic inhibitors. In this work, we analysed the potential of cysteine restriction (CysR) in the murine cell line L929. This study determined metabolic fingerprints using mass spectrometry (LC/MS). The profiles were compared with profiles created in an earlier work under MetR. The study was supplemented by proliferation studies using D-amino acid analogues and inhibitors of intracellular cysteine synthesis. CysR showed a proliferation inhibition potential comparable to that of MetR. However, the metabolic footprints differed significantly and showed that CysR does not induce classic LEM at the metabolic level. Nevertheless, CysR offers great potential as an alternative for decisive interventions in general and tumour metabolism at the metabolic level.

scholarly journals SYNTHESIS OF PARAMECIUM SURFACE PROTEINS

1973 ◽  
Vol 56 (2) ◽  
pp. 434-440 ◽  
Author(s):  
Irving Finger ◽  
Patricia Lavanchy ◽  
Ann Meany
Keyword(s):  
Amino Acid ◽  
Incubation Period ◽  
Turnover Rate ◽  
Surface Protein ◽  
Surface Proteins ◽  
Cell Protein ◽  
Double Labeling ◽  
Chase Period ◽  
Radioactive Amino Acid

The synthesis of a surface protein has been studied in Paramecium through double-labeling experiments using [14C]- and [3H]leucine-labeled bacteria as the source of radioactive amino acid. Over a 4–5 h incubation period, the turnover rate was found to be higher than that of overall cell protein. In addition, the initial label is apparently utilized during the chase period, being incorporated into protein via a puromycin insensitive pathway.

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