enzymes

Question 1

enzymes are …… and they are …… which ….. the speed if the chemical reaction in the bldy by …… and they are …. consumed

Answer 1

• gobular
• catalysts
• increase
  -?10 power 6 -10 power 12 folds
• not consumed

Question 2

some enzymes require — which are small organic compound or metal ions

Answer 2

co factors

Question 3

—- is a place where the enzymes fold and enzymes also have — by which it binds. its lined with the —– side chains that binds the substrate non-covalently and it forms —– complex and result in creation of a —– and the model is called —

Answer 3

• active site
• substrate
• amino acid
• ES complex ( enzyme-substrate complex )
• product
  ( the formula:
  E ( enzyme ) + S —> ES —> E+ P
• lock and key model

Question 4

the naming of the enzymes are based on:

Answer 4

1- the type of reaction catalysed followed by the suffix -ase as: hydrogenase , protease , transferase and reductase
2- name of the substrate as: gluckinase ( substrate is glucose ) and hexokinase ( substrate histoses)
3- the source of the enzyme: pancreatic lipase , salivary amylase
4- its regulation: hormone specific lipase
5- other names that are not obvious enzymes names as: trypsin, pepsin , thrombin

Question 5

the systematic name of the enzymes are based on —- this identifies the —– and —- involved and there are — classes of enzymes

Answer 5

• the International union of biochemist IUB
• type of reaction it catalysis and substrate envolved
• 6 classes which are:
  1- oxidoreductase
  2- transferase
  3- hydrolase
  4- lyase
  5- isomerase
  6- ligase

Question 6

—- transfers of electrons and hydrogen from one redox system to another

Answer 6

oxidoreductase

Question 7

—- move ( transfer ) groups from one moliducle to another as phosphate, amino , carboxyl

Answer 7

transferase

Question 8

—- cleavege of bond using water

Answer 8

hydrolase

Question 9

—- cleaveage of chemical bonds as: c-c , c-sulphur

Answer 9

lyase

Question 10

— rearrangement of binds

Answer 10

isomerase

Question 11

—- bond formation c and oxygen , sulphur , nitrogen

Answer 11

ligase ( sythesase)

Question 12

each enzyme has an optimum — for the biological activity , the velocity of the enzymatic reaction —- up to the point and then starts — due to protein denaturation

Answer 12

• temp
• increases
• decreasing

Question 13

each enzyme has an optimum — for the biological activity and the functions are mostly effective at their optimum.
the changes of this property may lead to:

Answer 13

• ph
• function of the active side amino acid side chain
• mat cause denaturation

Question 14

the enzyme kinetics is the rate of an enzyme reaction is the change in —- of the —— and —- per unit of —-

Answer 14

• concentration (M)
• product and substrate
• time ( min or s )
  formula :
  rate of reaction : decrease in substrate concentration/ change in time
  rate of reaction: increase in product concentration/ change in time

Question 15

— degrees is when proteins starts denutration
—- is the ph of pepsin
—- is the ph of trypsin
—- is the ph of alkaline phosphatase

Answer 15

• 50 degrees
• 2
• 6
• 9

Question 16

— is the number of substrate molecules converted into products per unit per unit of time and is expressed as —-

Answer 16

• enzyme rate or velocity
• micro molar ( uMol per min )

Question 17

— affects the enzyme rate , and as it increases the — of the reaction increases too.
this increase is — until it reaches platue where further increase in S does not proceed any increase in the rate of reaction , this occurs bc at low S the rate of reaction is — by the number of susbatre molecules available to bind to the active site

Answer 17

• [ S]
• increases
• linear
• limited
  ( check the graph its important )

Question 18

as the number of molecules the enzymes become — and all binding sites are constantly — by the substrate

Answer 18

• saturated , occupied

Question 19

the Michaels-menten equation plots the —- of the reaction against the different — result in a —

Answer 19

• rate of the reaction V
• substrate
• curve
  V = (Vmax + {s} / Km + {S} )

Question 20

—- can be estimated by the plateau of the curve
—- this is a substrate concentration at which the rate is half the v max

Answer 20

V max , Km

Question 21

— reflects the affinity of the enzyme for its substrate expressed in molar concentration

Answer 21

km

Question 22

low km indicates — which means only — concentration is needed of the substrate to saturate the enzyme

Answer 22

high affinity , low con needed
( check graph slide 15)

Question 23

—- is any substance that can diminish the velocity of an enzyme-cataysled reaction

Answer 23

inhibitor ( can be either competitive or non completive )

Question 24

— binds reversibly to the active site of the enzyme
enzyme is inhibited at — concentration
as the [s] — the inhibitor is displaced and the enzyme activity returns back to normal
— is increased
— remains unchanged

Answer 24

• compitive inhibtor
• low concentration
• rise
• km
• kmax

Question 25

--- is an inhibitor that binds to the site other than the active site of the enzyme which ---- the reaction rate , the --- remains unchanged while the ---- decreases

Answer 25

- non-competitive inhibitor - reduces - km - kmaxx

Question 26

in the presence of ----- inhibitor the vmax is decreased and the km remains the same while the effect cant be overcome by an increase of [s]

Answer 26

non-copetitev inhibitor

Question 27

in the presence of ---- inhibitor the km is increased as more substrate is needed to reach 1/2 the vmax and the kmax remains unchanged , the reaction velocity reaches the same vmax observed in the absence of the inhibitor , sufficiently high [s] the effect can be reversed by increasing [s]

Answer 27

competitive inhibitor

Question 28

---- are non proteins substance required for an enzymetic reaction to occur . they are often metal ions as: the organic cofactors are known as ----- such as:

Answer 28

- cofactors - copper and mg - coenzymes as vitamines , they are often involved in oxidation reduction reactions acting as electron donors or acceptors