Induced Fit model 86-108

what makes induced fit model different from lock and key model?

it has very specific substrate binding to specific enzyme and flexibility in the end structure of enzyme

When happens when substrate binds in induced fit model

Enzyme will move around it when substrate binds and determine end structure of enzyme

What does catalysts do

speed up rate of reaction without getting used up

what are enzymes made up of?

either polypeptides or polypeptides and non-protein complex

what are apoenzyme and cofactor

polypeptide portion of enzyme (protein portion); nonprotein portion

what are coenzyme

organic enzymes, associated more loosely with enzyme

holoenzyme

active, apoenzyme with coenzyme

what are Coenzymes good at?

good at transferring things from one substrate to another (electrons and functional groups)

what are the four important coenzymes

nad+, nadp+, fad, coenzyme A

what happens outside optimal zone for enzyme activity

the enzyme gets denatured

How is enzyme activity affected between high and low temperatures

more enzyme substrate interaction at high temperatures and denaturing, less interaction at low temperatures and slowed reactions

what does low km mean for affinity?

high affinity for substrate because you do not need substrate concentration to be high

what dos Vmax tell us

max rate when enzyme is fully saturated with substrate

what does km say?

substrate concentration to operate at half the maximum velocity

competitive inhibitor

compete with natural substrate at the active site, so structure is complementary enough

noncompetitive inhibitor

not competing with natural substate, will bind at allosteric site instead and make conformational change, which will change shape at active site

how do you overcome competitive inhibition

make more substrate

what does sulfa drug do?

it is an competitive inhibitor that will more likely bind to enzyme and there is higher affinity for sulfra drug over natural substrate

what does bacteriostatic mean (sulfra drug is considered this)?

doesn’t kill bacteria directly, but causing cells to not replicate so immune system can clear out microorganisms

what are the 3 major mechanisms for metabolic regulation

1) metabolic channeling (moving things around cell)

2) regulation of the synthesis of a particular enzyme (what level do we make enzyme)

3) direct stimulation or inhibition of enzyme

metabolic channeling is used in which cells?

prokaryotic cell

what does compartmentation do?

run pathways independently that are similar to one another

difference in Covalent modification from allosteric regulation

additional layer of control

2 reversible control measures for post translational regulation of enzyme activity

allosteric regulation (noncompetitive inhibition) and covalent modification

how does the molecule bind to the allosteric site in the allosteric regulation

non-covalently at regulatory site

what is covalent modification of enzymes?

when a chemical group is added or removed (that’s why it’s reversible) to turn enzyme on or off through covalent bond

when is feedback inhibition used? how does it work?

if not using end product

end product building will bind with enzyme and act as allosteric regulator and shut pathways down so that substrate will not bind

what does pacemaker enzyme do?

first enzyme in pathway that catalyzes the slowest reaction in pathway that feedback inhibition binds to

what is a branching pathway for feedback inhibition?

it can inhibit at first step but can also regulate at branch points themselves

What does each end product in branching pathway regulate?

regulate its own branch on the pathway and the initial pacemaker enzyme