LIFESCI 2N03 Lecture Notes - Glucogenic Amino Acid, Essential Amino Acid, Egg White
22 Nov 2013
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Greek derivative protos = of prime importance. 2nd most abundant components of plants and animals (2nd to water) Food sources: animal-based food (meat, fish, milk) Generally provide better protein than plant based; there are exceptions: plant sources dried beans, peas, nuts, seeds, some vegetables. Cysteine is made from methionine: amino acids are unique by their side chains, which dictate their size, shape, composition, electric charge and ph. Protein structure 4 levels: primary, formation of a dipeptide. Tripeptide = 3 amino acids: oligoeptide = 4-10 amino acids, polypeptide >10 amino acids, most natural polypeptides = 50-200 amino acids called a protein, eg/ polypeptide length = 200 amino acids (most common length) Number of different proteins = 20200: cross-linking by disulphide bridges. Eg/ insulin sequenced in 1953 by frederick sanger: secondary, additional formation of chemical bonds 2 resulting shapes. Lecture 7: -helix hydrogen bonds between n-h and c=o groups. Single chain with different chemical bonds between amino acids that are not adjacent.
