Enzymes

Enzymes

Biological catalysts

• made of proteins (sometimes RNA)

rate of reaction

Enzymes increase the ?

• more product in same amount of time

activation energy

Enzymes reduce ?

free energy, consumed

Enzymes do not change ? released or required nor are they ?

Substrate

Reactants for a specific enzyme

Lock and Key Model

Substrates precisely fit into the active site of a specific enzyme

Induced Fit Model

Substrate binds to an active site and both change shape slightly, creating an ideal fit

chemical

There is a ? fit between the active site and substrate

• temporary H-bonds and ionic bonds link

compartmentalize

Cells are organized into organelles to ? the enzymes

Activation Energy

Minimum amount of energy that must be added to reactants to start the chemical reaction

Allosteric Regulation

Regulation of an enzyme by a molecule that binds to a site other than an enzyme’s active site

• the molecule can increase / decrease enzyme activity

Carbohydrase

Enzyme that breaks down carbohydrates

Catalyst

Substances that increase the rate of a chemical reaction and are not used up

• all enzymes are catalysts but not all catalysts are enzymes

Coenzymes

non-protein organic substance that is necessary for an enzyme to work

Cofactors

Organic or inorganic substance (e.g. metal ion) that is necessary for an enzyme to work 

temperature, pH

Enzymes need an optimal ? and ? to work correctly

• if they don’t have the right conditions, they’ll denature or change in shape

Enzyme inhibitor

Substance that stops an enzyme from catalyzing a chemical reaction

Enzyme Regulators

Substances that affect the rate at which an enzyme catalyzes a chemical reaction

Lipase

Enzyme that breaks down lipids

Protease

Enzyme that breaks down proteins

Negative Feedback Loop

signal causes response that lowers signal

intermediate, product

sometimes an ? or ? of a pathway will act as an inhibitor of enzymes in that pathway