enzymes recap Flashcards
what are the enzyme inhibitors that are poisons
-potassium cyanide
-snake venom
how is potassium cyanide an enzyme inhibitor
potassium cyanide is hydrolysed by stomach acid to form hydrogen cyanide gas which dissociated to H+ and CN- ions. The CN- ions bind to an enzyme in the mitochondria, inhibiting the enzyme, inhibits aerobic respiration= death
how is snake venom an enzyme inhibitor
contains an inhibitor for acetylcholinesterase, this means acetylcholine is broken down and muscles continue contracting. This leads to paralysis and death due to suffocation as the breathing muscles are not working
what are the medicinal drugs which can inhibit and activate enzymes
-aspirin
-protease inhibitors
-nucleotide reverse transcriptase inhibitors
how does aspirin work
reduces swelling and pain. Contains salicylic acid which inhibits enzymes which catalyses the production of prostaglandins. Aspirin can also reduce blood clotting
how do protease inhibitors work
used to treat viral infections by preventing virus replication. Competitively inhibiting protease enzymes so viral proteins cannot be made
how does nucleotide reverse transcriptase work
inhibit enzymes involved in making DNA using viral RNA as a template. Used to treat HIV patients
state things about the intracellular enzyme, catalase:
-breaks down hydrogen peroxide to water and oxygen
-consists of 4 polypeptide chains and cone haem group
-found inside small vesicles called peroxisomes
state things about the extracellular enzyme, amylase:
-converts starch to maltose, found in salivary glands and the pancreas
-needs Cl- to function
state thing about the extracellular enzyme trypsin
trypsin is a protease released in the pancreas and acts in the lumen of the small intestine. Trypsin hydrolyses peptide bonds to break down proteins into amino acids
what is the prosthetic group Zn2+ used for
-Zn2+ is for carbonic anhydrase
-co2 + h2o —(carbonic anydrase)—> H2CO3 –> H+ + HCO3- (hydrogen carbonate ions)
some cofactors act as substrates- what does this mean?
that the cofactor and the substrate together form the correct shape to bind to the active site of the enzyme
what is the equation for rate of reaction
rate= 1/ time taken to reach end point
what are buffers
-buffers resist changes to pH
-buffer solutions maintain desired pH for investigating enzyme action
some enzymes are produced in inactive precursor form, what does this mean they need to do
before they can carry out their function, some of their amino acid groups need to be removed e.g. trypsin and pepsin
