They are organic catalysts
They affect the reaction by decreasing the decreasing the activation energy.
They are proteins
Many enzymes are conjugated protein
Proteins that consist of amino acids attached to other groups via covalent bonds) and have non protein coenzyme
Both components must be present for the enzyme to function
The molecule upon which an enzyme acts is called the substrate
Most enzyme catalyzed reactions are reversible
The product synthesized by an enzyme can be decomposed by the same enzyme.
An enzyme that synthesizes maltose from glucose can also hydrolyze maltose back to glucose
Lock and key theory
More use for explaining drug interactions with receptors and enzymes
Induced fit theory
Describes the active site as having flexibility of shape
Best pH and temperature
Pepsin works in 2 pH
Pancreatic enzymes work in 8.5 pH
if Competitor is present in a concentration comparable to concentration of the substrate, it will bind to active site and enzyme is inhibited by the inactive substrate. There should be much higher concentrations of substance than would be necessary without the competitor to out compete the competitor
Is a substance thar forms strong covalent bonds with an enzyme,making it unable to bind with its substrate, and it can not be displaced by the addition of excess substrate.
So noncompetitive inhibition is irreversible
When noncompetitive inhibition take placed at a site other than the active site, this is called allosteric inhibition
The interaction of an inhibitor at an allosteric site change the structure of the enzyme, so that the active site is also changed.
Lactose to glucose and galactose
Metal cations Zn 2*, Fe2*
Or coenzyme like as vitamin derivative
Cofactors that bind to the enzyme by strong covalent bonds are called prosthetic groups.