Biochemistry - Misc Vocab

Front 1

Main function of enzymes

Back 1

Lower the activation energy

Front 2

2 models of enzyme/substrate binding

Back 2

Lock and key
Induced fit

Front 3

4 types of specificity of enzymes

Back 3

Absolute = only 1 substrate
Group = group of similar molecules
Linkage = breakage or formation of certain bonds
stereochemical = distinguishes between 2 chiral forms (D and L)

Front 4

6 classes of enzymes

Back 4

Oxidoreductases - catalyse redox
Transferases - transfer functional groups
Hydrolases - addition of water to break bond
Lysases - addition or removal of groups to form double bond
Isomerases - One structural isomer to another
Ligases - join two molecules together

Front 5

Isoenzymes are......

Back 5

different forms of an enzyme which catalyse the same reaction
Often tissue specific

Front 6

4 ways that changes in pH affect enzyme activity
(BELL CURVE)

Back 6

1. Cause amino acids to change charge
2. breaks bonds (H bonds, Ionic bonds)
3. Changes charge of surface of protein - affects protein interactions
4. Affects charges on amino acids in active site

Front 7

The curve of temperature and enzyme function is NOT a ......

Back 7

bell curve

Front 8

Cofactors

Back 8

Non-protein groups required for enzyme function (metals, flavins, etc.)
bind covalently to enzyme and maintain configuration of active site

Front 9

Apoenzyme

Back 9

an enzyme without the cofactor

Front 10

Holoenzyme

Back 10

An enzyme with it's cofactor

Front 11

Co enzymes

Back 11

Organic molecules which serve as carriers of electrons or chemical groups
Subgroup of cofactors
NOT permanently bound - covalently bound

Front 12

4 regulation mechanisms for enzymes

Back 12

1. allosteric enzymes
2. Feedback inhibition
3. Production of zymogens
4. Phosyphorylation of enzymes (Covalent)

Front 13

Allosteric regulation

Back 13

Regulation of an enzyme which is regulated in the NON active site part of the enzyme

Front 14

Zymogens

Back 14

An enzyme that is produced in its inactive form.
Converted to active form by proteolysis

Front 15

Definition of metabolism

Back 15

The sum of all chemical equations going on within an organism
"Change" in Greek

Front 16

3 different kinds of metabolic pathways
2 main branches of metabolism

Back 16

1. simple (linear)
2. branched
3. cyclical

1. Catabolism (breaking down/lysis) (Divergent)
2. Anabolism (building up/genesis) (Convergent)

Front 17

Amphibolic

Back 17

a pathway that contains both anabolic and catabolic components
Krebs cycle

Front 18

4 principles of metabolism

Back 18

1. irreversible
2. committed step
3. regulated
4. specific cellular locations (compartmentalized)

Front 19

Main site of metabolism in the body?

Back 19

Liver
(blood glucose levels, protein metabolism, lipid metabolism, creates fatty acids from excess fuel and detoxes from drugs)

Front 20

Competitive Inhibitor
Same ____ but increased ______

Back 20

Resembles natural substrate and competes.
increasing substrate will overcome
Same V[max] but Increased K[m]

Front 21

Non-Competitive Inhibitor
Same _____ but decreased ______

Back 21

Not on active site - does not mimic substrate.
Binds weakly to amino acid R-groups or metal ion cofactors
CANNOT be reversed with more substrate
Same K[m] but decreased V[max]

Front 22

Uncompetetive Inhibition

Back 22

Inhibitor binds to ES complex but NOT to free enzyme
Parallel in LB plot
Both K[m] and V[max] decrease

Front 23

Mixed Inhibition

Back 23

Binding of inhibitor affects binding of substrate and vice versa
Lines intersect
K[m] increases, V[max] decreases

Front 24

Allosteric Enzymes and MM model?

Back 24

Kinetics cannot be explained by Michaelis Menton.
Sigmodal activity curve

Front 25

2 ways allosteric enzymes work

Back 25

Concerted - Active (R) to INactive (T) all change at once. ALl either R or T

Sequential - Changing active (R) to Inactive (T) conformation in one makes it easier for other to change. Mix in same molecule

Front 26

Unit of enzyme activity

Back 26

Micromoles substrate converted to product per minute
(umol/min)
Expressed as initial rate Vo

Front 27

Michaelis Menten Kinetics equation and formula
(2 equations and a formula)

Back 27

E+S =k[1]/k[-1] = ES = k[2] = E+P

Reversible in first step

Vo = V[max] [S] / ([S] + K[m])

K[m] = k[-1] + k[2] / k[1]

Front 28

4 assumptions of Michaelis Menten kinetics

Back 28

1. reaction assumes steady state (formation of ES = breakdown of ES [steady amount of ES])
2. not converted back into substrate
3. concentration of enzyme is much smaller than substrate concentration
4. [ET] (total) equals the concentration of free enzyme [E] plus the concentration of [ES]

Front 29

K[m] is?
3 things and units?
formula?

Back 29

The Michaelis constant.
Units are Molar
Measure of stability of enzyme substrate complex and affinity of enzyme for its substrate
K[m] = sum of rate constants for breakdown of ES/Sum of rate constants for formation of ES

Front 30

High Km and Low Km indicate?

Back 30

High Km = weak substrate binding
Low Km = strong substrate binding

Front 31

Turnover Number
and equation

Back 31

the number of substrate molecules converted into product by an enzyme in time period (under saturating substrate conditions)
k[cat] = V[max]/[ET]
= Number of moles mer sec converted/number of moles of enzyme

Front 32

Lineweaver Burk Plot
What intercepts, X and Y, and slope means
equation

Back 32

Equation: 1/Vo = Km/Vmax x 1/[S] + 1/Vmax

Y-intercept = 1/Vmax
X-intercept = -1/Km
Slope = Km/Vmax
X = 1/[S]
Y = 1/Vo

Front 33

Eadie Hofstee plot
Intercepts, X and Y, and slope?

Back 33

Equation: Vo = -Km(Vo/[S]) + Vmax
X = Vo/[S]
Y = Vo
Slope = -Km
Y-intercept = Vmax
X-intercept = Vmax/Km