1.The digestion and absorption of protein in the body is accomplished through amino acids: as the first nutrient element in the body, protein has an obvious role in food nutrition, but it cannot be used directly in the body. It is used by turning into small amino acid molecules.
2.play the role of nitrogen balance: when the quality and amount of protein in the daily diet are appropriate, the amount of nitrogen ingested is equal to the amount of nitrogen excreted from the feces, urine and skin, which is called the total balance of nitrogen. In fact, it is the balance between continuous synthesis and decomposition of protein and amino acids. The daily protein intake of normal people should be kept within a certain range. When the intake of food is suddenly increased or decreased, the body can still regulate the metabolism of protein to maintain nitrogen balance. Ingestion of excessive protein, beyond the body’s ability to regulate, the balance mechanism will be destroyed. If you do not eat protein at all, the tissue protein in your body will still be decomposed, and negative nitrogen balance will continue to occur. If you do not take corrective measures in time, the antibody will eventually die.
3.Conversion into sugar or fat: a-keto acid produced by the catabolism of amino acids is metabolized along the metabolic pathway of sugar or fat with different characteristics. a-keto acid can be re-synthesized into new amino acids, or converted into sugar or fat, or enter the tri-carboxy cycle to oxidize and decompose into CO2 and H2O, and release energy.
4.Participate in the formation of enzymes, hormones, and some vitamins: the chemical nature of enzymes is protein (amino acid molecular composition), such as amylase, pepsin, cholinesterase, carbonic anhydrase, transaminase, etc. The components of nitrogen-containing hormones are proteins or their derivatives, such as growth hormone, thyroid stimulating hormone, adrenaline, insulin, enterotropin and so on. Some vitamins are converted from amino acids or combined with proteins. Enzymes, hormones, and vitamins play a very important role in regulating physiological functions and catalyzing metabolism.
