Protein Biochemistry And Enzymology Flashcards
(36 cards)
What is the natural function of B-galactosidase?
To hydrolyse lactose
It also hydrolyses other galactosidases such as nitrophenylgalactose.
What is the enzyme-substrate complex equation?
Enzyme + substrate = Enzyme-substrate complex = Enzyme + product
What happens to the fraction of enzyme molecules bound to substrate as substrate concentration increases?
It increases
What does saturation of an enzyme indicate?
Most enzyme molecules have substrate bound
What does the Michaelis-Menten equation describe?
V = (Vmax)(substrate concentration / (Km + substrate concentration))
What does Km represent in enzyme kinetics?
Michaelis constant (units of concentration)
What does Kcat describe?
How fast the enzyme works (turnover rate)
What is the specificity constant formula?
Kcat / Km
What does a high specificity constant indicate about an enzyme?
High catalytic efficiency
What does a Lineweaver-Burk plot represent?
A double reciprocal plot used to determine enzyme kinetics
What is the effect of competitive inhibition on Vmax?
Vmax stays the same
What is the main characteristic of irreversible inhibition?
Inhibitors react covalently with essential groups in the enzyme
What condition is associated with the blockage of acetylcholine receptors?
Myasthenia gravis
What is the role of Edrophonium?
Competitive inhibitor of acetylcholinesterase used for diagnosis of Myasthenia gravis
What are the components of proteins?
Amino acids
What bonds join amino acids in proteins?
Peptide bonds
What is the secondary structure of proteins characterized by?
Alpha helix and beta sheets
Which amino acid is a helix breaker?
Proline (P)
What is the hydrophobic effect?
Most important determinant of tertiary structure
What is the significance of disulfide bonds in proteins?
Covalent bonds between two cysteine side-chains
What does the Henderson-Hasselbalch equation relate to?
pH, pKa, and the ratio of base to acid
What does isoelectric focusing rely on?
The isoelectric point (pI) where a molecule has no net charge
What is the purpose of SDS-PAGE?
To separate proteins based on their size
What type of chromatography uses a charged matrix?
Ion exchange chromatography
