Amino Acid And Nutrition

PROTEIN AND AMINO ACIDS

Protein, one of the five main nutrients, the others being carbohydrates, fat, vitamins and minerals is an indispensable material for life. The significance of protein is that it constitutes the structures of life and regulates the function of its activities, while carbohydrates and fat are used mainly for energy, and vitamins and minerals mainly are for the control of body functions. Protein is the structural basis of skeletal muscles and internal organs, including digestive organs.

Both enzymes (the catalyst which regulates metabolism) and hormones (the controller of metabolism) are either protein or peptides which have less molecular weight than protein.

Along with other nutrients, amino acids also synthesize nucleic acids in the body. They carry genetic information, and support the activities of life by controlling the order of synthesizing protein in the body.

When proteins are synthesized in the body, all kinds of necessary amino acids have to be present. Among these amino acids, some can be produced in the body and are called non-essential amino acids. The others, which can not be produced in the body or can be but insufficient in amount, must be ingested constantly and are thus called essential amino acids. If these essential amino acids are not ingested, the proteins to maintain life activities cannot be synthesized, causing various health problems. For instance, if the amount of protein in the blood goes down, anemia will result, and if the sufficient enzymes cannot be synthesized, the function of the digestive organs such as liver (the key for metabolism) will be weakened, causing fatigue and loss of appetite. The shortage of essential amino acids also causes the absence or shortage of antibodies I the blood, weakening the body resistance against various diseases.
 

The Dietetical Explanations and Metabolism of Amino Acids in the Human Body
Amino Acids	Dietetical Explanation	Metabolism
(ESSENTIAL)
Lysine	The first limiting amino acids for all kinds of grain. Most insufficient.	Inactive, an absolutely indispensible Amino acid and does not participate in transamination.
Threonine	The second limiting amino acid for rice. Insufficient next to Lysine.	Inactive. Same as above.
Methionine	The first limiting amino acid for soybeans. Added to animal feed.	A principal source of organic sulfur for the body (produces Cystine). Important for methylation of various compounds.
Tryptophan	The second limiting amino acid for corns, often insufficient in animal feed.	Precursor for serotonine which is a nervous hormone and has a potent effects on metabolism of the brain (produces Nicotine acid).
Phenylalanine	A large amount is contained in vegetable Protein. Sufficient to meet requirement.	Produces Tyrosine from which hormone and derivatives are produced and are very important.
Valine	Same as above.	Inactive.
Leucine	Same as above.	Inactive. Its metabolitic products participate in the synthesis of Cholesterol.
Isoleucine	Same as above.	Inactive.
(SEMI-ESSENTIAL)
Tyrosine	Synthesized from Phenylalanine.	Produces very important hormones and malanine.
Cystine	Synthesized form Methionine and Serine.	Produces Glutathione. Important in Oxidation reduction reaction. Has Detoxification effect.
FONT FACE="arial" SIZE="1">Arginine	The rate of its synthesis is relatively slow. Regarded as essential for children who require plenty of it.	Important in the urea synthesis, participates in the synthesis of Creatine.
Histidine	Same as above.	Important in synthesis of nucleic acids Precursor for Histamine, Urocanic acid And carnosine.
(NON-ESSENTIAL)
Glycine	Glycine and Serine are mutually convertible.	Important as a sythetic material of nucleic Acids, Hemoglobin and Creatine.
Alanine	Synthesized from pyruvic acid in the pathway of glycolysis.	The center of transamination.
Serine	Formed from posphoglyceric acid in the pathway of glycolysis.	Participates in the synthesis of nucleic acid, choline (precursor of nervous Hormone) and lipid such as lecitnine.
Proline	Formed from Glutamic acid.	In collagen (bonding organic protein of tendons) produces Oxyproline.
Aspartic Acid	Formed from oxaloacetic acid(in TCA-cycle).	Very active, the center of transamination and participates in TCA cycle, urea cycle and the synthesis of nucleic acid.
Asparagine	Formed from Aspartic acid.	Has a connection with the metabolism of ammonia.
Glutamic Acid	Formed from alpha-keto-glutaric acid(in TCA cycle).	Very active, the center of transamination, Participates in TCA cycle and urea cycle. Has an important function in brain.
Glutamine	Formed from Glutamic acid.	Particpates in the synthesis of nucleic acid and amino acid. Ammonia is detoxified by the formation of Glutamine from Glutamic acid.