cofactors and the mechanism of enzyme action Flashcards
cofactor
a substance that has to be present to ensure an enzymes reaction take ls place at the appropriate rate
what are prothetic groups
cofactors that are part of the enzymes structure
what are coenzymes
cofactors that form temporary associations with the enzyme
example of a prosthetic grop
carbonic anhydrase has a zinc ion permanently bound to its active site
what do cosubstrates do ?
they and the substrate together form the correct shape to bind to the active site.
what are the requirements for amylase to work?
chloride ions need to be present
what happens to the coenzymes after the catalysation?
they are chemically changed and need to be recycled
lock and key model (breaking bonds)
substrate fits into the active site. Temporary hydrogen bonds hold them together. The substrate molecule is broken down into products that leave active site.
lock and key model (forming bonds)
substrate molecules fit into the active site forming ES complex and bonds form between the substrate molecules. the larger product leaves the active site
who proposed the induced fit model?
Daniel Koshland
what is the induced fit hypothesis?
when substrates fit onto enzymes the active site changes giving it a good fit. like a glove fitting around a hand
what equation demonstrates how an enzyme catalyses a reaction?
E+S — ESC — EPC — E+P
how do enzymes lower the activation energy?
by bringing substates close enough together to react without the need of excessive heat
