Enzymes Imp Notes

Question 1

5 common features

Answer 1

Produced by living cells and can function outside
Small amounts needed
Biochemical reactions acceleration
Not equilibrium
Not chemically changed at the end
Highly specific

Question 2

Ribozymes is

Answer 2

RNA

Question 3

Co enzymes types
Proteins
Metals

Answer 3

Proteins» prosthetic ,tightly bound to enzyme»co-substrate loosely bound to apoenzyme
Metals»metalloenzymes, tightly bound, participate in catalysis» metal activated enzymes, loosely bound participate in substrate binding

Question 4

Is the delta G affected by enzymes

Answer 4

No

Question 5

Why and Vi

Answer 5

To avoid product accumulation and decrease in substrate and equilibrium

Question 6

Reversible inhobitors

Answer 6

Competitive> high Km
Non-competitive>low Vmax
Allosteric> either or, changes the enzyme

Question 7

Examples for reversible inhibitors

Answer 7

> > Allopurinol drug for gout that inhibits xanthine oxidase enzyme preventing the production of excess uric acid(competitive)
Phosphofructokinase enzyme and ATP(allosteric inhibitor)
AMP, fructose 2,6 BP(aloosteric activators)

Question 8

Irreversible inhibitors affecting cofactors

Answer 8

Flouride, blocks enolase enzyme in glycolysis by binding to ca2+ and Mg2+ to form salts,,No cofactor for enzyme, floride chelates the ions

Cyanide, carbon monoxide, inhibit cytochrome oxidase in ETC by binding to iron of heme

Question 9

Why are Blood test tubes are covered with NaCl

Answer 9

To prevent glucose oxidation

Question 10

Inhibitors that affect the apoprotein part are…and called…

Answer 10

Non specific
Enzyme poisons

Question 11

Anti Enzymes and inhibitors that denature

Answer 11

Anti Enzymes are specific for the enzyme like antithrombin III activated by heparin that inhibits blood clotting

Strong acid, alkali,alcohol,salt of heavy metal

Question 12

Inhibitors that block chemical groups
Enzyme poisons

Answer 12

Sulfhydryl groups SH>oxidising agents prevented by producing reducing agents like Glutathione

Block hydroxyl group> aspirin

Question 13

Aspirin

Answer 13

An reversible inhibitor by acytylation to the hydroxyl group of serine of cyclooxygenase enzyme which is important for prostaglandin synthesis
Anti inflammatory and antipyretic effect

Question 14

Zymogens/proenzymes

Answer 14

Inactive frames of enzyme requiring the removal of the polypeptide chain that masks the active site by proteolysis

Question 15

Activating proenzymes

Answer 15

Pepsinogen+HCl
Pepsin
Autocatalytic activation

Question 16

Isoenzymes

Answer 16

Catalyze the same reactions present in same or different cells
Different polypeptide chains/ genes/ migration rates /affinity to substrate/ affected differently by inhibitors and activators

Question 17

Lactate dehydrogenase LDH

Answer 17

4 subunits of H and M
Tetrameric enzyme
Only when 4 are present it is active
Isozyme 1> HHHH> cardiac origin, increases in myocardial infarction
Isozyme 5> MMMM> hepatic origin, increases in case of liver disease
Muscular origin, increases in muscular disease