Post Laboratory Report in Chem 40.1

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EXPERIMENT 1:
Proteins
-polypeptides compose of > 50 amino acids

Functions
1. Enzymes or subunits of enzymes-enhancing the rates of reactions 2. Structural or Mechanical roles
3. Immune response roles
4. Storage and transport of substances
5. Source of amino acids for organisms that cannot synthesize amino acids naturally

ISOLATION- disruption of cell membranes to release cell contents; separation for other contaminants 1. CENTRIFUGATION
2. SALTING OUT-water is made available to the protein by adding a salt solution of higher concentration 3. ISOELECTRIC PRECIPITATION- varying the pH conditions to reach protein pI * pI-pH at which the net charge of all its associate groups is equal * protein aggregates since the electrostatic repulsive forces are at a minimum. 4. Precipitation with organic solvents or acidic protein precipitants -addition of O.S decreases dielectric constant

PURiFICATION
1. Column chromatography
2. Density gradient centrifugation
3. Electrophoresis
4. enzymatic digestion
5. Removal of small ions or molecules or to exchange one ionic environment for another during purification is done by :Dialysis, Ultrafiltration and Gel filtration Dialysis-addition of NaOH and HClm

PROTEIN STRUCTURES
1. Fibrous –not water soluble: Collagen
2. Globular- mostly water soluble : Globulin, Hemoglobin and Albumin-Globular

A. Invertase- catalytic protein or enzyme that catalyzes the breakdown of sucrose sugar- mixture of fructose and glucose or inverted sugar syrup -industries and Invertase is usually denied from yeast; may also be synthesized from bees -Optimum temperature at which the catalyze rate is at its greatest is 60 o and with optimum pH of 4.5 - Sucrose -> Invertase-> glucose + fructose

B. Casein- globular proteins; tend to fold back on themselves into compact, nearly spherical units, relatively hydrophobic but easily solubilized in to as colloidal suspension....
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