MCAT Bio

• Can be overcome by increase [S]
• Reduces V
• Does not alter V_max
• Binds at active site

• Can not be overcome by increase [S]
• Reduces V_max
• Does not alter K_m

Removes a phosphate from a protein; this is covalent modification

• Breaks peptide bonds between amino acids
• Ex: Activation of Digestive Enzymes

Occurs viad the binding of a regulator molecule to an allosteric site of an enzyme and does not involve dephosphorylation

Occurs when the activity of an enzyme is continuously on; this can occur in response to an association with an activating subunit or dissociation from an inhibitory subunit

• = -RTlnK'_eq
• K'_eq = [C]_eq[D]_eq/[A]_eq[B]_eq

= G^o' + RTlnK, where K = [C][D]/[A][B]

-12kcal/mol

Protein-cleaving enzymes.  Many have an active site with a serine residue whose OH group can act as a nucleophile, attacking the carbonyl carbon of an amino acid residue in a polypeptide chain

The addition of a phosphoryl group from an ATP to the hydroxyl of serene, threonine, or tyrosine residues.  Phosphorylation on an enzyme can either activate or inactivate the enzyme.

phosphorylate proteins using free-floating inorganic phosphate (P_i) in the cell instead of ATP

• attach oxygen (or increase number of bonds to oxygen)
• remove hydrogen
• remove electrons

• remove oxygen (or decrease number of bonds to oxygen)
• add hydrogen
• add electrons

30 and 32

mitochondrial matrix

inner mitochondrial membrane

Cytoplasm of hepatocytes (liver cells)