Enzymes Flashcards
What is a holoenzyme?
active enzyme with its non protein component whereas the enzyme without its non protein component is said apoenzyme and it is inactive
What is a cofactor?
the non protein component is a metal ion such as Zn or Fe
What is a coenzyme?
small organic molecule
What is a cosubstrate?
Coenzymes that are only transiently associated with a substrate
What is a prosthetic group?
coenzyme is permanently associated with the enzyme
What is free energy of activation?
energy barrier separating the reagent energy level from that of the products
energy difference between that of the reactants and the high energy intermediate state that occurs during the formation of a product
What is allosteric regulation?
regulated by molecules called effectors that bind non-covalently to a site other than the active site
alter the affinity of the enzyme for its substrate or modify the maximal catalytic activity of the enzyme
What is covalent modification?
addition or removal of phosphate groups from specific serine, threonine and less frequently tyrosine residues
kinases catalyse the addition of phosphate group to these residues using ATP as source of phosphate groups
What is induction/ repression of enzyme synthesis?
changing their rate of synthesis or their rate of degradation
Metabolism
