Enzymes Flashcards
What are enzymes?
Protiens that act as biological catalysts for intra and extracellular reactions to determine strucutre and function. Therefore affect the metabolism of cells and whole organisms.
Specific tertiary structure determines shape of active site, complementary to a specific substrate
Formation of enzyme substarte complexes lowers activation energy of metabolic reactions
What is an example of an enzyme that catalyses intracellular reactions?
Catalase: catalyses decomposition of hydrogen peroxide into water and oxygen
What is an example of enzymes that catalyse extracellular reaction?
Amylase- carbohydrates catalyses digestion of startch to maltose in saliva/ small intestine lumen.
Trypsin- pancreatic endopetidase catalyses hydrolysis of peptide bonds in the small intestine lumen.
What are the 5 factors that affect the rate of enzyme-controlled recations?
Enzyme concentration Substrate concentration Concetration of inhibitors pH Temperature
What are cofactors?
Non-protein conpounds required for enzyme action:
Coenzymes
Inorganic cofactors
Prosthetic groups
What are coenzymes?
Organic cofactors. Do not bind permanently. Often transport molecules or electrons between enzymes.
Frequently derived from water-soluble vitamins
What are inorganic cofactors?
Facilitate temporary binding between substrate and enzyme. Often metal ions.
What are prosthetic groups?
Tightly-bound cofactors act as a permanent part of enzymes binding site
What are active sites?
indented area on the surface of an enzyme molecule, with a shape that is complementary to the shape of the substrate molecule.
What are catalysts?
A chemical that speeds up the rate of reaction and remains unchanged and reusable at the end of reaction.
What is a metabolism?
The chemical reactions that take place place inside living cells or organisms
What is an enzyme-substrate complex?
A complex formed by temporary binding of enzyme and substrate molecules during an enzyme-catalysed reaction.
Enzyme molecule with substrate molecule in its active site, The two are joined temporarily by non-covalent bonds.
What is an enzyme-product complex?
Enzyme molecule with product molecule(s) in its active site. The two are joined temporarily by non-covalent forces.
What is a buffer?
Something that resists the changes in pH.
What is the competive inhibition of enzymes?
Inhibition of an enzyme, where the inhibitor molecule has a similar shape to that of the substrate molecule and competes with the substrate for the enzyme’s active site. It blocks the active site and prevents the formation of enzyme-substrate complexes.
