The amino acid is a colorless crystal having a melting point of more than 200 ° C, which is much higher than the melting point of a general organic compound. The α-amino acid has four different tastes of acid, sweet, bitter and fresh. Monosodium glutamate and glycine are the most abundant flavorings. Amino acids are generally soluble in water, acid solutions and alkaline solutions, insoluble or slightly soluble in organic solvents such as ethanol or ether.
The solubility of amino acids in water varies greatly. For example, the solubility of tyrosine is the smallest. At 25 ° C, tyrosine in 100 g of water only dissolves 0.045 g, but the solubility of tyrosine in hot water towel is large. Lysine and arginine are often present in the form of hydrochlorides because they are highly soluble in water and are difficult to crystallize due to deliquescence.
Essential amino acid: refers to the inability of the human body (or other vertebrates) to synthesize or synthesize at a rate that is far from being adapted to the body. It must be supplied by food proteins, which are called essential amino acids. The amount of essential amino acids required for adults is about 20% to 37% of the protein requirement. There are 8 kinds of roles that are:
Lysine: promotes brain development, is a component of liver and gallbladder, can promote fat metabolism, regulate pineal gland, breast, corpus luteum and ovary to prevent cell degradation;
Tryptophan: promote the production of gastric juice and pancreatic juice; phenylalanine: participate in the elimination of kidney and bladder function loss; methionine (methionine): participate in the composition of hemoglobin, tissue and serum, promote spleen, pancreas and lymph Function; threonine: has the function of transforming certain amino acids to balance.
Isoleucine: involved in the regulation and metabolism of the thymus, spleen and subarachnoid; the general headquarters of the sub-genus gland acts on the thyroid gland, the gonad; leucine: the action balance isoleucine; proline: acts on the corpus luteum, Breast and ovary.