Enzymes: Biological Catalysts, Functions, and Applications

Enzyme

a biological catalyst that speeds up chemical reactions and helps to break down/build molecules.

Substrate

the substance that reacts with an enzyme.

Active Site

a pocket/groove in an enzyme that binds to the substrate.

Induced-Fit Hypothesis

describes how enzymes change shape to better attach to a substrate.

Enzyme-Substrate Complex

term used to describe enzymes bonded to substrate(s).

Cofactor

non-protein group that binds to enzymes and helps them function, often metals such as copper, iron, zinc etc.

Coenzyme

an organic molecule that acts as a cofactor of an enzyme, may be derived from vitamins.

Competitive Inhibitor

binds to active site directly to prevent substrate from binding.

Non-competitive Inhibitor

binds to enzyme and changes its shape, indirectly prevents substrate from binding.

Irreversible Inhibitors

often highly toxic to cells as they prevent enzymes from functioning (Ex. Cyanide binds to cytochrome oxidase and interferes with cellular respiration).

Allosteric Regulation

regulation of enzyme function using other molecules that bind to the enzyme.

Allosteric Site

a binding site on an enzyme where allosteric molecules attach.

Allosteric Inhibition

stabilizes enzyme into an inactive form.

Allosteric Activation

stabilizes enzyme into an active form.

Feedback Inhibition

the regulation of a pathway by one of the products of the pathway.

Temperature and pH

can both affect enzyme activity; enzymes will often only function optimally within a specific range of temperatures and pH levels.

Lactase

an enzyme used to help break down lactose in dairy products.

Making Cheese

enzymes used to solidify milk into cheese.

Breaking Down Starch

enzymes used to break down plant starches into sugars.

Stain Removal

used to break apart certain types of staining molecules without heating (Cold Water Detergents).

Enzyme Activity Rate

may occur at a rate of 100 to 10 million molecules per second!