I. Proteins
Function of body protein: antibodies in the immune system, muscle contraction and movement, enzymes that facilitate biochemical reactions (catalysts), hormones that regulate bodily activities, structural proteins that provide support, such as with keratin and collagen, found in connective tissues, storage proteins store amino acids, transport proteins carry molecules/nutrients from one place to another (i.e. hemoglobin). Also contributes to acid base balance as buffers. Forms glucose through gluconeogenesis. Muscle wasting is cachexia. Protein also provides 4kcal/g
Protein sources in the diet: Either diet or recycling of body protein. In NA, 70% is by meat, poultry, fish, milk and milk products, legumes, nuts. Worldwide though only 35% of protein comes from animals.
General protein structure and chemical bonds: Contains hydrogen, oxygen, carbon, and nitrogen. Comprised of amino acids, a nitrogen (amino) group, a carboxyl (acid) group, a hydrogen, and a side chain (R) which determines protein function and name
Primary structure, which is order of amino acids. Secondary structure, where weaker bonds between amino acids form spiral-like or pleated sheets. Tertiary structure is the 3D folding. Quaternary structure is multiple protein molecules.
Denaturation of a protein: means to alter the protein’s 3-dimensional structure. Caused by acid, alkaline, heat, enzymes, or agitation. Adaptation of protein synthesis describes the constant state of breakdown, rebuilding, and repair in response to diet, exercise, etc.
Essential vs. nonessential amino acid: Nonessential, or dispensable amino acids, the body can produce. Essential, or indispensable amino acids, must be taken in through food. Conditionally essential amino acids are those essential during infancy, disease, or trauma.
Essential include histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine. Non-essential include alanine, arginine,