biochem 2 Flashcards by Jaylin Chlosta

Four main features of Enzymes

catalysts
efficient
specific
potent

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Enzymes are catalysts that increase the reaction rate by reducing __________?

activation energy

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Examples of enzymes functioning as catalysts

Globular proteins
RNA (ribozymes)

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At what rate are enzymes faster than a regular reaction

10^3 to 10^17

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T/F Enzymes have side reactions

FALSE

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T/F Enzymes do not alter equilibrium

TRUE

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Enzymes are specific in the sense that they have a limited range of ___________ to produce ______________ products

substrates/ specific

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Example of the potency of enzymes: carbonic anhydrase produces ________/ sec from bicarbonate

1,000,000

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Enzymes lower _____________ energy

activation

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Enzymes have no effect on __________________ of the reaction

overall energy change

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With an enzyme what increases and what remains the same

reaction rate increases
equilibrium constant remains the same

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T/F enzymes can catalyze a reaction even when it is unfavorable

FALSE

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Enzymes act to _______ the activation energy and ________ the transition state

lower/ stabilize

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when delta G is < 0 the reaction is

favorable

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when delta G is > 0 the reaction is

unfavorable

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when delta G = 0 the reaction is

at equilibrium

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T/F if one reaction is not favorable but has a product that participates in a favorable reaction, the reactions can be linked together to force the original reaction to completion

TRUE

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Cofactors are

non amino acid components that provide a reaction with chemistry that the R group cannot

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Co-factors and prosthetic groups must be ___________ is chemically altered

regenerated

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Cofactors contain

2 enzymes
2 reactions

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prosthetic groups contain

one enzyme (stays attached)
two reactions

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True catalysts cannot undergo ______ ________ ________: cofactors must be ____________________

permanent chemical change
regenerated

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In an enzymatic kinetic graph, the curve levels off when the reaction _______________

reaches equilibrium

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Km =

[S] at Vmax/2

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When an enzyme has a high Km it has a __________ affinity for the substrate

lower

When an enzyme has a low Km it has a __________ affinity for the substrate

high

Why is the M&M equation / analysis helpful

1. Elucidate physiological role of enzymes 2. Study inhibition action for therapeutics

Where is glucokinase found and at what [] does it work best at

liver, B cells of pancreas [High]

Where is hexokinase found and at what [] does it work best at

most tissue including liver [low]

What is the physiological relevance of gluc/hex

the higher Km of gluc. allows the liver to respond to increases in glucose to capture extra glucose when hex is saturated

Km of Hex and Km of Gluc

~1 mM and ~7mM

What are isozymes

distinct enzymes that catalyze the same biochemical reaction

Isozymes exist within ______, within an. individual at different stages of development, within the same __________ or even same ________

species. tissue, cell

Isozymes can have subtle or significant differences in __________

primary structure

How can you distinguish isozymes

kinetics/ regulatory properties

Creatine Kinase can be found in ______ and _________

myocardial infarction and muscle disorders

Lactate Dehydrogenase can be found in both

muscle disorders, liver disease

The pharmaceutical actions of drugs are due to their ability to ___________ enzymes specifically

inhibit

Alkaline phosphatase can be found in both

liver disease and bone disease

Inhibitors can be

general or specific

Examples of general enzyme inhibitors

metal ions, organic solvents, acids, alkalis

General enzyme inhibitors inactive enzymes _______ and _________ that can still be studied ____________

irreversibly and non-spontaneously kinetically

How do general inhibitors work

protein denaturation

T/F general inhibitors have medical relevance

FALSE

Specific enzyme inhibitors ________ the substrate of their target enzyme

mimic

SEI may bind in two ways

1. at the active center but be unable to react any further 2. Bind and react. to form a product the will not dissociate from the enzyme so that it can no longer participate in anything else

T/F enzymes can bind inhibitors with greater affinity than they can bind the substrate

TRUE... this is bc the I can mimic the TS.

Specific inhibitors can be

reversible or irreversible (suicide)

Irreversible Inhibitors ___________ bind to active center

covalently ex. nerve gas

Competitive inhibitors bind to active center via

non covalent bonds

T/F High [S] can outcompete I in comp inhib

true

Non competitive inhibitors bind _____ to the substrate via ________ bonds

distal, non-covalent

T/F High [S] can outcompete I in non comp inhib

FALSE

Competitive inhibitors bind to ________, ___________ kM, and changes the ________ intercept

E, increases, X

Non competitive inhibitors bind to ________, ___________ Vmax, and changes the ________ intercept

E and ES, decreases , Y

The contact or intrinsic pathway is for trauma ________ of the vascular system that leads to bleeding

inside

The tissue factor/ extrinsic pathway is for trauma ______ of the vascular system that leads to bleeding. ex. endothelial tissue

outside

What is an essential cofactor in the blood clotting cascade

Vit. K

T/F blood clotting is reversible even thought thrombin undergoes irreversible PTM

TRUE

What degrades fibrin clots

plasmin

Genetic Coagulation Disorders

Hemophilia (A, B and C) Von Willebrand Disease

Hemophilia A and B are _______ recessive and C is ___________

x linked recessive, autosomal

What factors do all types of Hemophelia use

A - factor VIII B - factor IX C - factor XI (rare)

Von Willebrand Disease is a

platelet adhesion defect

Acquired Coagulation Disorders (4)

Vitamin K deficiency Liver Disease Anemia Low platelet count

Autocrine cells target _________ Paracrine cells target _________ Gap Junctions target _________ Endocrine cells target _________

itself (immune cells, stem cells, cancer) cells nearby (cell proliferation, differentiation) adjacent cells (embryonic, organ tissue) distant cells (hormonal signaling)

GPCR are __________ that are used by cells to convert extracellular signals into intercellular responses

intergral membrane proteins

GPCR are common

drug targets

Beta Adrenergic Receptor are made up of

catecholamines and epinephrine

what does Beta Adrenergic Receptor stimulate

nervous system alert

4 main functions of the fight or flight response

dilate blood vessels increase heart rate divert blood to skeletal muscle energy mobilization

Heterotrimeric G(aby) proteins serve what purpose

signal transduction and amplification

G alpha is active when bound to ________ and inactive when bound to ___________

GTP, GDP

Ga interacts with 7TM GPCR to do what

stimulate GDP --> GTP exchange

Intrinsic GTPase activity is the ______ conversion from active to ________ state and is stimulated by ___________

slow, inactive, Regulator of G Protein Signaling (RGS)

What Ga subfamily stimulates cAMP

Gas

What Ga subfamily inhibits cAMP

Gai

What Ga subfamily activates phospholipase

Gaq

What Ga subfamily activates Rho GTPase

Ga12/Ga13

___________ is a membrane protein stimulated by Gas

Adenylyl Cyclase

AC catalyzes the conversion of ATP to

3'-5' cAMP

Step 1 of the B adrenergic receptor

Ligand (epinephrine) binds to the b-adrenergic receptor

Step 2 of the B adrenergic receptor

B adrenergic receptor undergoes a conformational change

Step 3 of the B adrenergic receptor

activates Ga protein by GDP to GTP exchange

Step 4 of the B adrenergic receptor

Ga-GTP dissociates from Gby

Step 5 of the B adrenergic receptor

Ga activates adenylyl cyclase

Step 6 of the B adrenergic receptor

Production of cAMP

Step 7 of the B adrenergic receptor

Activation of PKA

Ways to turn off the B adrenergic receptor

feedback inhibition GTP hydrolysis via RGS Dissociation of the ligand from the receptor Desensitization

3 types of neurons

sensory, motor and interneurons

During action potential, neuron to neuron is _____________ gated

ligand

Action potentials. along the axon are _______________________

voltage gated

__________________ local anesthetic diffuses. across a membrane. _______________ LA binds to channels

deprotonated, protonated

pka of LA is

~8-9

Voltage gated NA+ is important for _________ and __________ function

cardiac function, brain function

term for the oxidation of the iron in hemoglobin

methemoglobin

biochem 2 Flashcards

(97 cards)