enzymes Flashcards
enzymes are …… and they are …… which ….. the speed if the chemical reaction in the bldy by …… and they are …. consumed
- gobular
- catalysts
- increase
-?10 power 6 -10 power 12 folds - not consumed
some enzymes require — which are small organic compound or metal ions
co factors
—- 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 —
- active site
- substrate
- amino acid
- ES complex ( enzyme-substrate complex )
- product
( the formula:
E ( enzyme ) + S —> ES —> E+ P - lock and key model
the naming of the enzymes are based on:
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
the systematic name of the enzymes are based on —- this identifies the —– and —- involved and there are — classes of enzymes
- 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
—- transfers of electrons and hydrogen from one redox system to another
oxidoreductase
—- move ( transfer ) groups from one moliducle to another as phosphate, amino , carboxyl
transferase
—- cleavege of bond using water
hydrolase
—- cleaveage of chemical bonds as: c-c , c-sulphur
lyase
— rearrangement of binds
isomerase
—- bond formation c and oxygen , sulphur , nitrogen
ligase ( sythesase)
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
- temp
- increases
- decreasing
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:
- ph
- function of the active side amino acid side chain
- mat cause denaturation
the enzyme kinetics is the rate of an enzyme reaction is the change in —- of the —— and —- per unit of —-
- 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
— degrees is when proteins starts denutration
—- is the ph of pepsin
—- is the ph of trypsin
—- is the ph of alkaline phosphatase
- 50 degrees
- 2
- 6
- 9
— is the number of substrate molecules converted into products per unit per unit of time and is expressed as —-
- enzyme rate or velocity
- micro molar ( uMol per min )
— 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
- [ S]
- increases
- linear
- limited
( check the graph its important )
as the number of molecules the enzymes become — and all binding sites are constantly — by the substrate
- saturated , occupied
the Michaels-menten equation plots the —- of the reaction against the different — result in a —
- rate of the reaction V
- substrate
- curve
V = (Vmax + {s} / Km + {S} )
—- can be estimated by the plateau of the curve
—- this is a substrate concentration at which the rate is half the v max
V max , Km
— reflects the affinity of the enzyme for its substrate expressed in molar concentration
km
low km indicates — which means only — concentration is needed of the substrate to saturate the enzyme
high affinity , low con needed
( check graph slide 15)
—- is any substance that can diminish the velocity of an enzyme-cataysled reaction
inhibitor ( can be either competitive or non completive )
— 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
- compitive inhibtor
- low concentration
- rise
- km
- kmax
— 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
- non-competitive inhibitor
- reduces
- km
- kmaxx
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]
non-copetitev inhibitor
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]
competitive inhibitor
—- 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:
- cofactors
- copper and mg
- coenzymes as vitamines , they are often involved in oxidation reduction reactions acting as electron donors or acceptors
