Biochemistry Kay Iwelumo
Objectives Proteins- Composition/Structure Protein Purification Enzymes- Kinetics and Inhibition Hemoglobin/Myoglobin Membrane- Structure & Function Metabolism/Metabolic Pathways
Proteins Primary Secondary Tertiary Quaternary Amino acids Characterized by polar vs. nonpolar, negative vs. postively charged terminals Can you identify?
Proteins Purification Use assays to monitor presence of protein Can be purified based off of solubility, charge, size, binding affinity Positive result on assay means protein is present Step 1: Disrupting cell membrane, forming homogenate Centrifugation to separate based on density Fractions separately assayed for desired activity Step 2: Salting out Dialysis Gel Filtration chromatography Ion exchange chromatography Affinity chromatography Step 3: Testing whether purification is effective Gel electrophoresis SDS Page
Purification Methods Dialysis Gel-Filtration Chromatography
Hemoglobin and Myoglobin Deoxy(T-state) Oxy (R-state) Hemoglobin shifts between states when carrying Oxygen from lungs to tissues 2,3-BPG is an allosteric inhibitor in hemoglobin Binding curves differ
Enzymes Catalyze reactions without changing equilibrium Facilitate the formation of a transition state- decreasing activation energy Inhibitors Michaelis- Menten Kinetics Potent Inhibitor- V max K m V max K m
Membrane Transport Mechanisms Membrane Structure Boundaries of a cell Selective permeability Hydrophobic and hydrophilic lipid components Restrict flow of polar molecules Proteins can serve as pumps, channels and carriers Various types of transport
Metabolic Pathways Glycolysis Gluconeogenesis Cori Cycle Glycogen in muscles lactic acid Sent through blood to liver Converted to glycogen Can be converted to glucose & sent to muscles Or stored Energy conversion pathways Considered reciprocal pathways Glycolysis- a glucose molecule is converted to 2 pyruvate molecules– 2 ATP Gluconeogenesis-synthesizes glucose from 2 pyruvate liver Consumes ATP Reciprocally regulated to prevent wasting ATP