Metabolism / Enzyme Regulation 10/22

Define metabolism

The sum of all biochemical reactions in a cell

catabolism

complex materials are broken down to simpler component

catabolic reactions

what is broken in catabolic rxns

c-c bond (carbon to carbon)

c-p bond (carbon to phosphate)

what is released when catabolic rxns are broken

energy

another name for catabolic rxns

degradative

anabolism

simple components assembled into complex material

anabolic rxns

another name for anabolic rxns

biosynthetic rxns

what is made in anabolic rxns

c-c bond

c-p bond

what doe anabolic rxns require

energy in form of ATP

ATP name

adenosine triphosphate

ATP reversible reaction is

ATP < - > ADP+ phosphate (adenosine diphosphate)

two main ways metabolic pathways can be structured

linear and circular

metabolic pathways need enzymes because

they don’t happen spontaneously so not favorable on there own

enzymes

catalyze rxns by lowering activation energy (Ea)

enzymes are

proteins

enzymes are referred to as

biological catalysts

because they are biological catalysts they are

not alive (found in living systems)

can be damaged reversible or irreversible

enzymes are

substrate specific

where does substrate bind on enzyme

active site

where do cofactors/coenzymes bind on enzyme

allosteric site (second site)

after everything binds on enzyme…

rxn proceeds

in competitive inhibition

an enzyme active site can be filled by correct or incorrect substrate

when correct enzyme fills active site

it becomes activated and produces product

when incorrect enzyme fills active site

no reaction

what happens to enzyme if incorrect substrate is binded

its not functional , nothing it can do to boot out incorrect substrate

A factor that determines if incorrect or correct substrate will bind

concentration (amount)

Another factor that determines if incorrect or correct substate will bind

proximity

in noncompetive inhbition

enzymes have active site and allosteric site

cofactor is

molecule in addition to substrate that is required for a rxn to proceed

in noncompetitive w/ activator…

enzyme is normally off until activator turns it on

in noncompetitive w/ activator when activator binds to allosteric site…

the shape of active site changes, allowing substrate to bind

if activator doesn’t bind

rxn cannot happen

in noncompetitive w/ inhibitor…

enzyme is normally on unless inhibitor binds to allosteric site and changes shape

if inhibitor binds to allosteric site

the enzyme is turned off

when there is no inhibitor present

the substrate can bind to active site and reaction proceeds

when there is a inhibitor

the substrate cannot bind to active site and reaction doesn’t proceed proceeds

feedback inhibition/regulation

a product or intermediate later in pathways inhibits a step early in pathways

feedback inhibition includes

competitive and noncompetitive with inhibitor

what can’t we have as part of feedback inhibition

noncompetitive with activator

why can’t noncompetitive with activators be present within feedback inhibition

an activator cannot inhibit an enzyme