Term
| Henderson-Hasselbach Equation |
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Definition
| pH = pKa + log([A-]/[HA]) |
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Term
| Explain the hydrophobic effect. |
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Definition
| When hydrophobic molecules are placed in water, they will aggregate together. This is an endothermic reaction that increases the entropy (randomness) of the system. This is because when there is a single hydrophobic molecule, the water around it has fewer H-bonding options than in pure water. When the hydrophobic molecules aggregate together, some of these ordered water molecules are displaced, which increases the randomness (entropy) of the system. This is a spontaneous reaction. |
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Term
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Definition
| A characteristic of a molecule containing both a polar and a nonpolar region. |
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Term
| If the pH is less than the pKa, is the molecule protonated or deprotonated? |
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Definition
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Term
| If the pH is greater than the pKa, is the molecule protonated or deprotonated? |
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Definition
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Term
| If the pH is less than the pI, what is the overall charge of the molecule? |
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Definition
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Term
| If the pH is greater than the pI, what is the overall charge of the molecule? |
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Definition
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Term
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Definition
| The change in free (useable) energy |
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Term
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Definition
| Change in the total energy of the system |
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Term
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Definition
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Term
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Definition
| The change in entropy (randomness, unuseable energy) |
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Term
| If delta G is less than zero, is the reaction spontaneous or nonspontaneous? |
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Definition
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Term
| If delta H is less than zero, is the reaction endothermic or exothermic? |
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Definition
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Term
| Where are the psi, phi, and omega angles in a peptide, and what do positive or negative torsion angles indicate? |
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Definition
Psi is on the side of the carboxy group connected to the alpha carbon. Omega is on the side of the carboxy group connected to the amino group. Phi is on the side of the amino group connected to the alpha carbon.
Positive torsion angles indicate that the R group is rotating clockwise.
Negative torsion angles indicate that the R group is rotating counterclockwise. |
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Term
| What does beta-mercaptoethanol do? |
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Definition
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Term
| What treatment is given to polypeptides that have been treated with beta-mercaptoethanol, and what does this do? |
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Definition
| They are treated with iodoacetic acid to protect the -SH groups. |
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Term
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Definition
| Cleave internal peptide bonds |
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Term
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Definition
| An endopeptidase that cleaves the C-terminus of Lys or Arg |
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Term
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Definition
| An endopeptidase that cleaves the C-terminus of Phe, Tyr, or Trp |
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Term
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Definition
| Reacts with the N-terminus amino acid. It is fluorescent. Treatment is followed by reduction of disulfide bonds and total hydrolysis (which cleaves all peptide bonds). |
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Term
| Does total hydrolysis tell us the sequence of amino acids in a peptide chain? |
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Definition
| No. It does not tell us the order; only the identity of the amino acids. |
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Term
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Definition
| An endopeptidase that cleaves at C-terminus of ala, gly, ser, val |
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Term
| Which amino acid(s) can pancreatic enzymes not cleave? |
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Definition
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Term
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Definition
| Cleave N- or C-terminal residues |
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Term
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Definition
| Cleaves C-terminal residue of protein |
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Term
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Definition
Cleaves at C-terminus of methionine residues.
*Limitation: met residues not common in nature |
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Term
| Compare and contrast fibrous vs. globular proteins. |
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Definition
Property Fibrous Globular
Flexibility static dynamic
Shape long & straight compacted
H2O Solubility insoluble soluble
Hydrophobicity in & exterior mostly interior
Strength tough, solid spongy, flexible
Function support selective binding
Examples collagen enzymes
alpha-keratin antibodies |
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Term
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Definition
| An enzyme without a cofactor |
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Term
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Definition
| A complete, catalytically active enzyme |
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