ACS BIOCHEMISTRY Solved Exam |100% Pass|

ACS BIOCHEMISTRY Solved Exam |100% Pass| Henderson-Hasselbach Equation *Ans* pH = pKa + log ([A-] / [HA]) FMOC Chemical Synthesis *Ans* Used in synthesis of a growing amino acid chain to a polystyrene bead. FMOC is used as a protecting group on the N-terminus. Salting Out (Purification) *Ans* Changes soluble protein to solid precipitate. Protein precipitates when the charges on the protein match the charges in the solution. Size-Exclusion Chromatography *Ans* Separates sample based on size with smaller molecules eluting later. Ion-Exchange Chromatography *Ans* Separates sample based on charge. CM attracts +, DEAE attracts -. May have repulsion effect on like charges. Salt or acid used to remove stuck proteins. Hydrophobic/Reverse Phase Chromatography *Ans* Beads are coated with a carbon chain. Hydrophobic proteins stick better. Elute with non-H-bonding solvent (acetonitrile). Affinity Chromatography *Ans* Attach a ligand that binds a protein to a bead. Elute with harsh chemicals or similar ligand. SDS-PAGE *Ans* Uses SDS. Gel is made from cross-linked polyacrylamide. Separates based off of mass with smaller molecules moving faster. Visualized with Coomassie blue. SDS *Ans* Sodium dodecyl sulfate. Unfolds proteins and gives them uniform negative charge. Isoelectric Focusing *Ans* Variation of gel electrophoresis where protein charge matters. Involves electrodes and pH gradient. Protein stops at their pI when neutral. FDNB (1-fluoro-2,3-dinitrobenzene) *Ans* FDNB reacts with the N-terminus of the protein to produce a 2,4-dinitrophenol derivative that labels the first residue. C