CHEM-2221 Lecture Notes - Lecture 25: Strecker Amino Acid Synthesis, Pyridoxal Phosphate, Isoelectric Point
27 May 2016
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Document Summary
25. 1 classification of amino acids: the -amino acids are the building blocks of peptides and proteins. Amino acids: the amino acids are linked through an amide bond with the carboxylic acids of one aa with the -amino group of a second. Peptide or protein (polypeptide: peptide (< 50 amino acids, protein (> 50 amino acids) Stereochemistry: the natural configuration of the -carbon is l. In the fischer projection, the carboxylate is drawn on top, the r group on the bottom and the amino group is on the left. Ammonium ion acts as an acid, the carboxylate as a base: at different ph the protonation state of the aa changes. Isoelectric point (pi) - the ph at which the amino acid exists largely in a neutral, zwitterionic form. Reactions: many enzymes are involved in amino acid biosynthesis, many are pyridoxal phosphate (vitamin b6) dependent.
