Muscle proteins biosynthesis

In times of starvation, muscle tissue is usually quite inactive, so its energy demands are low. In fact, under such conditions the muscles tend to supply energy to the rest of the organism via degradation of muscle protein to amino acids. These amino acids are transported to the liver where they are converted to glucose or used for biosynthesis of other proteins essential for maintenance of the organism s vital processes. 

The nutritional consequences of an excess protein diet are the same as those of an excess carbohydrate or excess fat diet lipid biosynthesis and fat deposition. Additionally, the protein amino groups must be detoxified and eliminated. The nutritional consequences of a diet lacking complete protein—that is, one that doesn t supply the essential amino acids in the proportions needed for synthesis of proteins and neurotransmitters—also include excess ammonia generation. In this case, muscle proteins are degraded to supply enough of the limiting essential amino acid. The other amino acids are broken down, with the carbon chains metabolized into carbohydrates (and, potentially lipid). The leftover amino groups must then be eliminated as urea. 

GH stimulates incorporation of labelled amino acids into protein in skeletal muscle (diaphragm) from hypophysectomized rats in vitro [41,84], The effect is a consequence of stimulation of protein biosynthesis, although amino acid transport is also affected. Insulin and somatomedins also stimulate protein synthesis in diaphragm [44], but there are clear-cut differences between the actions of these hormones and of GH. Thus a 30 min lag period is characteristic of the action of GH, as is a refractory. period after 2-3 h of stimulation. 

Lomako, J., Lomako, W. M., and Whelan, W. J. 1988. A self-glucosylating protein is the primer for rabbit muscle glycogen biosynthesis. FASEB. J. 2, 3097-3103. 

Anabolic steroids increase the deposition of protein as muscle or protein biosynthesis. 

Certain bonds in ATP store the energy released during the oxidation of carbohydrates, lipids, and proteins. ATP molecules act as energy carriers and deliver the energy to the parts of the cell where energy is needed to power muscle contraction, biosynthesis, and other cellular work. 

The ATP molecule is a universal energy carrier in the cell, and it is the principal one. It will sustain all reactions and processes requiring Gibbs energy active ion transport (ion pump operation), biosynthesis of proteins and other substances, muscle contraction, and so on. It is also employed for temporary energy storage in the cell. 

El-Sebae, A.H., M.H. Salem, M.R.S. El-Assar, and E.E. Enan. 1988. In vitro effect of profenofos, fenvalerate and dimilin on protein and RNA biosynthesis by rabbit liver and muscle tissues. Jour. Environ. Sci. Health B23 439-451. 

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