scholarly journals Important Role of the Amino Acid Attached to tRNA in Formylation and in Initiation of Protein Synthesis inEscherichia coli

1996 ◽  
Vol 271 (2) ◽  
pp. 1022-1028 ◽  
Author(s):  
Shihong Li ◽  
N. Vinay Kumar ◽  
Umesh Varshney ◽  
Uttam L. RajBhandary
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Inescherichia Coli

scholarly journals BIOSYNTHESIS IN ISOLATED ACETABULARIA CHLOROPLASTS

1972 ◽  
Vol 54 (2) ◽  
pp. 279-294 ◽  
Author(s):  
David C. Shephard ◽  
Wendy B. Levin
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Technical Problems ◽  
Hydrolyzed Protein ◽  
Protein Amino Acids ◽  
Amino Acid Labeling ◽  
Labeling Pattern

The ability of chloroplasts isolated from Acetabulana mediterranea to synthesize the protein amino acids has been investigated. When this chloroplast isolate was presented with 14CO2 for periods of 6–8 hr, tracer was found in essentially all amino acid species of their hydrolyzed protein Phenylalanine labeling was not detected, probably due to technical problems, and hydroxyproline labeling was not tested for The incorporation of 14CO2 into the amino acids is driven by light and, as indicated by the amount of radioactivity lost during ninhydrin decarboxylation on the chromatograms, the amino acids appear to be uniformly labeled. The amino acid labeling pattern of the isolate is similar to that found in plastids labeled with 14CO2 in vivo. The chloroplast isolate did not utilize detectable amounts of externally supplied amino acids in light or, with added adenosine triphosphate (ATP), in darkness. It is concluded that these chloroplasts are a tight cytoplasmic compartment that is independent in supplying the amino acids used for its own protein synthesis. These results are discussed in terms of the role of contaminants in the observed synthesis, the "normalcy" of Acetabularia chloroplasts, the synthetic pathways for amino acids in plastids, and the implications of these observations for cell compartmentation and chloroplast autonomy.

Control of Muscle Protein Synthesis as a Result of Contractile Activity and Amino Acid Availability: Implications for Protein Requirements

2001 ◽  
Vol 11 (s1) ◽  
pp. S170-S176 ◽  
Author(s):  
Michael J. Rennie
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Muscle Protein ◽  
Contractile Activity ◽  
Muscle Protein Synthesis ◽  
Protein Requirements ◽  
Amino Acid Availability ◽  
Separate Pathway

The major anabolic influences on muscle are feeding and contractile activity. As a result of feeding, anabolism occurs chiefly by increases in protein synthesis with minor changes in protein breakdown. Insulin has a permissive role in increasing synthesis, but the availability of amino acids is crucial for net anabolism. We have investigated the role of amino acids in stimulating muscle protein synthesis, the synergy between exercise and amino acid availability, and some of the signaling elements involved. The results suggest that muscle is acutely sensitive to amino acids, that exercise probably increases the anabolic effects of amino acids by a separate pathway, and that for this reason it is unlikely that accustomed physical exercise increases protein requirements.

Dietary protein considerations for muscle protein synthesis and muscle mass preservation in older adults

2020 ◽  
pp. 1-11 ◽  
Author(s):  
Eunice T. Olaniyan ◽  
Fiona O’Halloran ◽  
Aoife L. McCarthy
Keyword(s):  
Older Adults ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Muscle Mass ◽  
Protein Intake ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Adult Population ◽  
Anabolic Resistance

Abstract Amino acid bioavailability is critical for muscle protein synthesis (MPS) and preservation of skeletal muscle mass (SMM). Ageing is associated with reduced responsiveness of MPS to essential amino acids (EAA). Further, the older adult population experiences anabolic resistance, leading to increased frailty, functional decline and depleted muscle mass preservation, which facilitates the need for increased protein intake to increase their SMM. This review focuses on the role of proteins in muscle mass preservation and examines the contribution of EAA and protein intake patterns to MPS. Leucine is the most widely studied amino acid for its role as a potent stimulator of MPS, though due to inadequate data little is yet known about the role of other EAA. Reaching a conclusion on the best pattern of protein intake has proven difficult due to conflicting studies. A mixture of animal and plant proteins can contribute to increased MPS and potentially attenuate muscle wasting conditions; however, there is limited research on the biological impact of protein blends in older adults. While there is some evidence to suggest that liquid protein foods with higher than the RDA of protein may be the best strategy for achieving high MPS rates in older adults, clinical trials are warranted to confirm an association between food form and SMM preservation. Further research is warranted before adequate recommendations and strategies for optimising SMM in the elderly population can be proposed.

Role of Leucine in Protein Metabolism During Exercise and Recovery

2002 ◽  
Vol 27 (6) ◽  
pp. 646-662 ◽  
Author(s):  
Donald K. Layman
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Branched Chain Amino Acids ◽  
New Findings ◽  
Branched Chain

Exercise produces changes in protein and amino acid metabolism. These changes include degradation of the branched-chain amino acids, production of alanine and glutamine, and changes in protein turnover. One of the amino acid most affected by exercise is the branched-chain amino acid leucine. Recently, there has been an increased understanding of the role of leucine in metabolic regulations and remarkable new findings about the role of leucine in intracellular signaling. Leucine appears to exert a synergistic role with insulin as a regulatory factor in the insulin/phosphatidylinositol-3 kinase (PI3-K) signal cascade. Insulin serves to activate the signal pathway, while leucine is essential to enhance or amplify the signal for protein synthesis at the level of peptide initiation. Studies feeding amino acids or leucine soon after exercise suggest that post-exercise consumption of amino acids stimulates recovery of muscle protein synthesis via translation regulations. This review focuses on the unique roles of leucine in amino acid metabolism in skeletal muscle during and after exercise. Key words: branched-chain amino acids, insulin, protein synthesis, skeletal muscle

The response of muscle protein synthesis to nutrient intake in postabsorptive rats: The role of insulin and amino acids

1986 ◽  
Vol 6 (2) ◽  
pp. 177-183 ◽  
Author(s):  
V. R. Preedy ◽  
P. J. Garlick
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Intravenous Infusion ◽  
Nutrient Intake ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Acting In Concert ◽  
Fasted Rats

In 12 h fasted rats, rates of muscle protein synthesis were stimulated by refeeding for 1 h and by intragastric or intravenous infusion of an amino acid plus glucose mixture for 1 hr, but not by intravenous infusion of amino acids alone for 1 h. Intravenous injection of anti-insulin serum suppressed the response to feeding and to intragastric infusion, but not to intravenous infusion. It is concluded that the response of muscle protein synthesis to food intake is mediated by both insulin and amino acids acting in concert.

Regulation of protein synthesis inEscherichia coli by amino acid analogues

1960 ◽  
Vol 5 (4) ◽  
pp. 207-216 ◽  
Author(s):  
J. Janeček ◽  
J. Chaloupka ◽  
K. Vereš ◽  
M. Havbánek
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Inescherichia Coli ◽  
Amino Acid Analogues

scholarly journals The Reverse Side of a Coin: “Factor-Free” Ribosomal Protein Synthesis In Vitro is a Consequence of the In Vivo Proofreading Mechanism

Biomolecules ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 588
Author(s):  
Finkelstein
Keyword(s):  
Quality Control ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Ribosomal Protein ◽  
Elongation Factor ◽  
Ribosomal Protein Synthesis

This paper elucidates a close connection between two well-known facts that until now have seemed independent: (i) the quality control (“proofreading”) of the emerging amino acid sequence, occurring during the normal, elongation-factor-dependent ribosomal biosynthesis, which is performed by removing those Aa-tRNAs (aminoacyl tRNAs) whose anticodons are not complementary to the exhibited mRNA codons, and (ii) the in vitro discovered existence of the factor-free ribosomal synthesis of polypeptides. It is shown that a biological role of proofreading is played by a process that is exactly opposite to the step of factor-free binding of Aa-tRNA to the ribosome-exposed mRNA: a factor-free removal of that Aa-tRNA whose anticodon is not complementary to the ribosome-exhibited mRNA codon.

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