BME 20100 Chapter Notes - Chapter 3.1: Carboxylic Acid, Alpha And Beta Carbon, Absolute Configuration

• School: Purdue University
• Department: Biomedical Engineering
• Course: BME 20100
• Professor: Harbin

Document Summary

All have similar structure: carboxyl group and amino group bonded to same c. All common ones except for glycine, alpha carbon is bonded to: carboxyl group, amino group, r group and a hydrogen atom. L, d system does aldehyde group of l-glyceraldehyde. Can be classified on their polarity (r groups) Alpha carbon is chiral center (4 different groups can occupy 2 unique spatial arrangement) Refer to absolute configuration of the 4 substituents around the chiral carbon. Polar, uncharged: more hydrophilic due to tendency to form h-bonds with water. Amino acids are amphoteric (act as both acid and base) Some amino acid residues in a protein may be modified to alter protein"s function charged. First stage: -cooh group loses proton (h+) to become -coo(-) Phenomenon exploited in active sites of enzymes. Relationship between amino acid"s net charge and ph of solution can be seen. Isoelectric point/ph (pi): the characteristic ph at which net charge is 0.