Proteins
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There are 20 common amino acids that are used to build proteins in the human body. Of these 20 amino acids, 9 are considered essential amino acids that cannot be synthesized by the body and must come from dietary sources. These are: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. The remaining 11 amino acids are non-essential, meaning the body can synthesize them from other metabolic precursors if they are not obtained from the diet. When we consume protein-rich foods, the proteins are broken down during digestion into their constituent amino acids. 1 The body can then use this pool of amino acids obtained from the diet (both essential and non-essential) as building blocks to synthesize thousands of its own specific proteins by linking the amino acids together in a coded sequence. Proteins are made of amino acids arranged in a linear chain joined by peptide bonds. Many proteins are enzymes that catalyze the chemical reactions in metabolism. Other proteins have structural or mechanical functions, such as those that form the cytoskeleton, a system of scaffolding that maintains the cell shape. Amino acids contribute to cellular energy metabolism by providing a carbon source for entry into the citric acid cycle (tricarboxylic acid cycle), especially when a primary source of energy, such as glucose, is scarce, or when cells undergo metabolic stress.
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All nitrogen-containing compounds of the body are synthesized from amino acids - cellular proteins, hormones (e.g., thyroxine, epinephrine, insulin), neurotransmitters,
creatine phosphate, heme in hemoglobin and cytochromes, melanin, purine and pyrimidine bases. Amino acids always contain carbon, nitrogen, hydrogen, and oxygen; most contain sulfur and
some include phosphorus. Amino acids are the building blocks of protein.
The amount of protein you eat for your first meal strongly predicts the amount of calories you’ll consume the rest of the day. More protein = fewer calories. Proteins are the main building blocks of your body, as well as enzymes, hormones, neurotransmitters, and various molecules. Proteins consist of amino acids, which link together like beads on a string, form long chains and fold into complex shapes. Protein is not only about quantity but also quality. The pancreas juices break down these proteins into seperate amino acids.
Enzymes are a special kind of protein that help chemical reactions happen more quickly, but only work in the right conditions. Each cell takes the amino acids is needs from the blood and build new proteins from them. The ribosomal proteins are indispensable components that provide structural integrity, functional capabilities, and regulatory control to the ribosome, enabling it to accurately synthesize proteins based on the genetic code.
The Non-essential amino acids
Twelve amino acids present in proteins are synthesized in the body - eleven (serine, glycine, cysteine, alanine, aspartate, asparagine, glutamate, glutamine, proline, arginine, histidine) are produced from glucose carbon skeletons, one (tyrosine) is produced from phenylalanine.
The Essential amino acids
Ten amino acids present in proteins (arginine, histidine, isoleucine, leucine, threonine, lysine, methionine, phenylalanine, tryptophan, valine) are required in the diet of a growing human.
the advice of triathlete and nutrition scientist Asker Jeukendrup, Ph.D. A side benefit: Adding protein to anything you eat effectively lowers its glycemic index, says Chris Jordan, M.S., C.S.C.S., director of exercise physiology for the Johnson & Johnson Human Performance Institute.
Book: Protein and Amino Acids https://www.ncbi.nlm.nih.gov/books/NBK234922/ (opens in a new tab)