Studied by 2 people
enzymes
globular protein that acts as a biological catalyst
activation energy Ea
the en barrier to be overcome for a rxn to occur & to form products
enz lowers Ea
signif to living organisms? slow rate of metabolic rxns at biological temps (37) → too slow to support demands → enzs lower Ea → rapid enough to support.
nature of enzs
can be reused, small amt req
specificity
enz catalysed rxn is reversible
readily denatured
active sites & proteins
specific 3d shape. shape of active site is complementary to substrate.
active site lined w aa residues & proteins → R groups bind to sub.
es complex: 2 models
lock & key — falsified (says only 1 enz to 1 sub, but actl can w similarly shaped subs)
induced-fit model — enz can slightly change its conformation to be more complementary to shape of the sub & return to org after.
enz activity
to note:
collisions, effective collisions
formation of es complex
rate of reaction
temp (KE, opt, denature)
ph: slight (alters charge of AA residues at active site → prevents formation of ES complex) vs large changes (denature)
sub conc (at high — all active sites occupied)
enz conc
denaturation
disruption of the 3d shape → loss of biological activity
bonds that maintain sec & tertiary structure are broken (H, ionic, disulphide). loses conformation
denatured, enz is non functional
immobilised enzs
advs: higher enz conc for higher rate, can be reused, resistant to denaturation over larger range of ph & temp
eg. lactose free milk: process — lactase from yeast, alginate beads, milk run over, lactose broken down, enzs can be reused
advs for milk: maintain org taste, reduce wastage. can be used as sweetener, shorten prod time for yogurt / cheese.
commercial applications: asia/africa, higher lactose intolerance
