Chapter 1: Enzymes

Pharmaceutical Biochemistry

Enzymes

• are biological catalysts that speed up the rate of biochemical reaction

Globular Proteins

• most enzymes are three dimensional ___________ (tertiary and quarternary structures)

Active Site

• is the region that bins substances, cofactors and prosthetic groups and contain residues that help hold the substrate

Less than 5%

Active site generally occupy __________ of the total surface area of enzyme.

Binding Site

• it chooses the substrate and binds it to active site

Catalytic Site

• it performs the catalytic action of enzyme

Cofactors

• it is the nonprotein molecule which carries out chemical reactions that cannot be performed by standard 20 amino acids

Inorganic Cofactors

• these are the inorganic molecules that required for the proper activity of enzymes

Zinc

Carbonic Anhydrase requires ________ for its activity.

Magnesium

Hexokinase has a cofactor _________.

Organic Cofactors

• these are the organic molecules that required for the proper activity of enzymes

Pyridoxal Phosphate

• glycogen phosphorylase requires the small organic molecule ________________.

Prosthetic Group

• a tightly bound organic cofactor

Coenzyme

• a loosely bound organic cofactor

Apoenzyme

• the inactive, protein component of an enzyme that requires a non-protein cofactor to become fully functional

Holoenzyme

• complete, active enzyme complex formed by an apoenzyme and its associate cofactor

Holoprotein

• biologically active, functional form of a protein that has its nonprotein id prosthetic group or cofactor attached

Substrate

• the reactant in biochemical reaction

Intracellular Enzymes

• are synthesized and retained in the cell for the use

Oxydoreductase

• catalyses biological oxidation

Extracellular Enzymes

• are synthesized in the cell but secreted from the cell to work externally

Pepsin, Trypsin and Rennin

Some enzymes were named before a systematic way of naming enzyme was formed, give three examples: