Enzyme Function, Kinetics, and Regulation

A complete set of vocabulary flashcards covering enzyme terminology, functional classes, reaction kinetics, inhibition, pathway regulation, and clinical applications from Chapters 1 through 6.

Cofactors and Coenzymes

Metallic compounds (such as zinc, copper, and iron) present in small amounts in the active site of enzymes that assist in moving electrons and carrying out biological functions.

Pyruvate Dehydrogenase

An enzyme that pulls water off of pyruvate, identifiable as an enzyme by its -ase suffix.

DNA Polymerase

An enzyme that joins nucleotides together to synthesize polymers of DNA.

Lipases

Enzymes that specifically act on lipids.

Amylases

Enzymes that break down amylose or starch.

Ligases

A functional class of enzymes that carry out synthesis reactions by bonding molecules together.

Opto Reductases

Enzymes that carry out oxidation-reduction (redox) reactions by transferring electrons.

Transferases

Enzymes that transfer chemical groups or components from one molecule to another, mediating single and double displacement reactions.

Kinases

A specific type of transferase enzyme that moves a phosphate group ($P_i$) onto a molecule or enzyme, serving as an on-off regulatory switch.

Hydrolases

Enzymes that break down chemical bonds in molecules through the addition of water.

Isomerases

Enzymes that rearrange the internal chemical bonds within a single molecule to form an isomer.

Isomer

A molecule that possesses the same molecular formula as another but has a restructured bond arrangement.

Reaction Rate

The measure of time needed to convert reactants into products.

Substrate

The specific reactant molecule that binds to an enzyme's active site to undergo a reaction.

Saturation

The state reached when all enzyme molecules are operating at maximum pace, meaning additional substrate concentration will not further increase the reaction rate.

Optimal Temperature

The specific temperature at which human enzymes function most efficiently, typically around $98.6^{\circ}\text{F}$.

Denaturing

The process where high temperatures or extreme pH (excess hydrogen or hydroxyl ions) deform an enzyme's shape and active site, causing it to lose its catalytic function.

Competitive Inhibitor

An inhibitor molecule that directly binds to the active site of an enzyme, competing with and blocking the substrate from entering.

Non-competitive Inhibitor

An inhibitor molecule that binds to an allosteric site on an enzyme, deforming the active site so that the substrate cannot bind.

Allosteric Site

A regulatory binding site on an enzyme separate from the active site that alters active site conformation when bound by an inhibitor.

Metabolic Pathway

A linked sequence of enzymatic reactions where an initial substrate is modified by specialized enzymes in step-by-step order to yield an end product.

Feedback Loop

A negative feedback regulation mechanism where the end product of a metabolic pathway binds to an allosteric site on an upstream enzyme to stop further production.

Multi-enzyme Complexes

Large groups of bound enzymes working together to execute complex processes, such as cellular respiration in mitochondria.

Phosphorylation

The addition of a phosphate group ($P_i$) to an enzyme or molecule by a kinase to regulate its function.

Dephosphorylation

The removal of a phosphate group ($P_i$) from an enzyme or molecule.

Phosphatases

Enzymes responsible for removing phosphate groups ($P_i$) from molecules during dephosphorylation.

Statins

A class of drugs (such as crevastatin) that inhibit enzyme activity to lower the body's natural production of cholesterol.

Lactase

The enzyme responsible for breaking down lactose into glucose and galactose.

Lactose Intolerance

A digestive condition caused by a lack or insufficient quantity of lactase, resulting in lactose fermentation by bacteria in the large intestine to produce acid and gas.