6.4 Regulation of Enzyme Activity in Biochemistry

These flashcards cover key concepts related to enzyme regulation in biochemistry, including definitions and explanations of important terms and processes.

Enzyme Regulation

The process through which enzyme activity is controlled, including mechanisms such as allosteric regulation and covalent modification.

Allosteric Regulation

A form of regulation where enzyme activity is modified by the binding of molecules to sites other than the active site, changing the enzyme's shape.

Covalent Modification

A regulatory mechanism involving the addition or removal of chemical groups, such as phosphorylation, to alter enzyme activity.

Bioavailability

The amount of enzyme present within a cellular compartment, which affects enzyme activity.

Catalytic Efficiency

The measure of how effectively an enzyme converts substrates into products during a reaction.

Zymogen

An inactive precursor of an enzyme, which requires a biochemical change to become active.

Proteolytic Activation

A regulatory process wherein inactive zymogens are activated by irreversible cleavage of peptide bonds.

Adenylylation

The addition of an adenylyl group to an enzyme, often resulting in decreased activity, as seen in glutamine synthetase.

Uridylylation

The addition of a uridylyl group that regulates the activity of certain enzymes, particularly glutamine synthetase adenylyltransferase.

Aspartate Transcarbamoylase (ATCase)

An enzyme regulated by allosteric effects, which demonstrates cooperative binding behavior.

Cooperativity

A phenomenon in enzymes where the binding of substrate to one active site affects the binding at other active sites, often resulting in sigmoid kinetics.

Phosphorylation

The process of adding a phosphate group to a protein or other organic molecule, which can alter enzyme activity.

T-state and R-state

The two conformational states of ATCase, with the T-state being inactive and the R-state being active.

Kinases

Enzymes that catalyze the transfer of phosphate groups, often activating or deactivating other proteins.

Phosphatases

Enzymes that remove phosphate groups from proteins, usually reversing the effect of kinases.