1S [LEC]: Enzymes (intro + CK + LDH) Flashcards by 3sha Ann

Biological molecules that act as catalysts, facilitating and accelerating chemical reactions within living organisms

Enzymes

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Specific proteins that catalyze biochemical reaction without altering the equilibrium point of the reaction or being consumed or changed in composition

Enzymes

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Refers to the number, type, and sequence of amino acids in the polypeptide chain

Primary structure

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Refers to the commonly formed arrangements stabilized by hydrogen bonds between nearby amino acids within the protein molecule

Secondary structure

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Refers to the overall shape of the protein molecule

Tertiary structure

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The structure that results from the interaction of more than one protein molecule, or protein subunits

Quaternary structure

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The substance acted upon by the enzyme

Substrate

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A water free cavity, where the substrate interacts with particular charged amino acid residues

Active site

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A cavity other than the active site

Allosteric site

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Binds the regulator molecules

Allosteric site

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T/F: Regulator molecules change enzyme conformation

True

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Enzymes with the same function but exist in different forms

Isoenzyme

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Forms of enzymes that were post-transcriptionally modified

Isoforms

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Non-protein molecule necessary for enzyme activity such as activators and coenzymes

Cofactors

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A coenzyme bound tightly to the enzyme

Prosthetic group

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The enzyme portion that is activated by the prosthetic group

Apoenzyme

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Prosthetic group + apoenzyme

Holoenzyme

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Inactive precursor of an enzyme

Zymogen/ Proenzyme

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Classify the enzyme:

Catalyze an oxidation-reduction reaction between two substrated

Oxidoreductase

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Classify the enzyme:

Catalyze the transfer of a group other than hydrogen from one substrate to another

Transferase

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Classify the enzyme:

Catalyze hydrolysis of various chemical bonds

Hydrolase

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Classify the enzyme:

Catalyze removal of groups from substrates without hydrolysis

Lyases

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Classify the enzyme:

Catalyze the interconversion of geometric, optical, or positional isomers

Isomerase

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Classify the enzyme:

Catalyze the joining of two substrate molecules

Ligase

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Classify the enzyme: Lactate dehydrogenase

Oxidoreductase

Classify the enzyme: Glucose-6-phosphate dehydrogenase

Oxidoreductase

Classify the enzyme: Glutamate dehydrogenase

Oxidoreductase

Classify the enzyme: Creatine kinase

Transferase

Classify the enzyme: Alkaline phosphatase

Hydrolase

Classify the enzyme: Acid phosphattase

Hydrolase

Classify the enzyme: a-Amylase

Hydrolase

Classify the enzyme: Cholinesterase

Hydrolase

Classify the enzyme: Chymotrypsin

Hydrolase

Classify the enzyme: Elastase-1

Hydrolase

Classify the enzyme: 5' nucleotidase

Hydrolase

Classify the enzyme: Aldolase

Lyase

Classify the enzyme: Triosephosphate isomerase

Isomerase

Classify the enzyme: Glutathione synthetase

Ligase

If the reaction is substrate dependent, it is ___-order kinetics

first

If the reaction is enzyme dependent, it is ___-order kinetics

zero

If the reaction is substrate independent, it is ___-order kinetics

zero

If the reaction is enzyme independent, it is ___-order kinetics

first

Curve of velocity versus substrate concentration for enzymatic reaction

Michaelis-Menten curve

Curve that is a transformation of Michaelis-Menten curve

Lineweaver Burk

A compound that shares some structural feature found in the substrate will typically physically bind to the same form of the enzyme that the substrate binds

Competitive inhibitory

Inhibitors associated with enzymes showing allosteric inhibition

Noncompetitive inhibitor

Identify the type of inhibition based on Lineweaver Burk curve change: Same Vmax Increased Km

Competitive

Identify the type of inhibition based on Lineweaver Burk curve change: Vmax not achieved & decreased Same Km

Noncompetitive

Identify the type of inhibition based on Lineweaver Burk curve change: Vmax not achieved Decreased Km

Uncompetitive

Size of CK

82 000 Daltons

CK isoenzyme: Most cathodal

CK-MM

CK isoenzyme: Least anodal

CK-MM

CK isoenzyme: Most anodal

CK-BB

CK isoenzyme: Least cathodal

CK-BB

CK isoenzyme: Most numerous

CK-MM

CK isoenzyme: Bound to the exterior surface of the inner mitochondrial membranes of muscle, brain, and liber

Mitochondrial CK

CK isoenzyme: Migrate cathodal to CK-MM

Mitochondrial CK

Macro-CK migrate midway ___ and ___

CK-MM CK-MB

Method of isoenzyme measurement: May visualize adenylase kinase

Electrophoresis

Adenylase kinase is cathodal to ___

CK-MM

Method of isoenzyme measurement: Reference method

Electrophoresis

Method of isoenzyme measurement: More sensitive and precise if done properly

Ion exchange chromatography

Method of isoenzyme measurement: Measure enzyme concentration rather than activity

Immunoassays

Method of isoenzyme measurement: Double Ab immunoinhibition

Immunoassay

Immunoassays measure Abs against which subunits?

M and B

Forward CK method with an optimum pH of 9

Tanzer Gilvarg

Reverse CK method that is 2-6x faster and has an optimum pH of 6.8

Oliver Rosalki

Analyte that is markedly increased in RBC disorder

LDH

Catalyzes the interconversion of lactic and pyruvic acids by transferring hydrogen using the coenzyme NAD+

LDH

LD forward method

Wacker method

LD reverse method that is 3x faster

Wroklewski La Due method

A phenomenon where LD 1 has a higher amount than LD 2

Flipped pattern

Flipped pattern is most commonly observed in what condition?

Heart (AMI) & RBC disease

LD isoenzyme that is cathodal to LD5 and is a hallmark of arteriosclerotic CVD

Alcohol dehydrogenase (LD6)

Macro-LD is found between ___ and ___

L3 L4

Classify the enzyme: Glycogen phosphorylase

Transferase

Classify the enzyme: Pyruvate kinase

Transferase

Classify the enzyme: Trypsin

Hydrolase

The intermediate state formed after the reactants exist

Transition state

The excess energy needed to induce the transition state

Activation energy

Specificity where the enzyme combines only one substrate and catalyzes only the one corresponding reaction

Absolute specificity

Specificity where the enzyme combine with all substrates containing a particular functional group, such as a phosphate ester

Group specificity

Specificity where the enzyme predominantly combine with only one optical isomer of a certain compound

Stereoisomeric specificity

Hypothesized the role of substrate concentration in formation of the enzyme-substrate complex

Michaelis and Maud Menten

A constant for a specific enzyme and substrate under defined reaction conditions an can provide an expression of the relationship between the velocity of an enzymatic reaction and substrate concentration

Michaelis-Menten constant

The ___ is specifically the substrate concentration at which the enzyme yield half the possible maximum velocity

Michaelis-Menten constant (Km)

A temperature increase of ___ will approximately double the enzymatic reaction

10C

The rate of denaturation increases as the temperature increase s and usually is significant at what range of temperature?

40-50C (but some may denature at body temp, 37C)

T/F: Low temperatures render enzymes irreversibly inactive

False (reversibly inactive)

Serve as secondary substrate for enzymatic reactions

Coenzymes

The method of enzyme determination where the reactants are combined, the reaction proceeds for a designated time, the reaction is stopped, and a measurement is made of the amount of reaction that has occurred

Fixed-time method

The method of enzyme determination where multiple measurements, usually of absorbance change, are made during the reaction, at specific time intervals

Continuous monitoring/ Kinetic assays

T/F: Kinetic methods are more advantageous than fixed-time methods

True

Conventional unit for enzymatic activity

IU (International Unit)

SI unit for enzymatic activity

Katal

Conversion factor from IU to nano katal

1 IU = 17 nano katal

Increased CK isoenzyme in Duchenne Muscular Dystrophy

CK-MM

Predominant CK isoenzyme in the heart

CK-MM

CK isoenzyme that is an indicator of severe illness, malignant tumor, and cardiac abnormalities

Mitochrondrial CK

The Macro CK is comprised of which CK isoenzyme?

CK-MM

The Macro CK is complexed with immunoglobulins, namely ___

IgG and IgA

In CK forward method, the enzyme is measured through the ___ in absorbance

Decrease (since the reaction will be NADH >>> NAD)

In CK reverse method, the enzyme is measured through the ___ in absorbance

Increase (since the reaction will be NAD >>> NADH)

Effect of hemolysis in CK measurement

False increase

Reference range for total CK

Male: 46-171 U/L Female: 34-145 U/L

Reference range for CK-MB

<5% total CK

LD isoenzyme increased in RBC disorders

LD1, LD2

LD isoenzyme increased in lung, spleen, and pancreatic problems

LD3

LD isoenzyme increased in liver and skeletal muscle conditions

LD4, LD5

In LD forward method, the enzyme is measured through the ___ in absorbance

Decrease (NADH >>> NAD rxn.)

In LD reverse method, the enzyme is measured through the ___ in absorbance

Increase (NAD >>> NADH)

What is the most labile LD isoenzyme?

LD5

Coenzyme in LD determination

NAD+

LD 5 losses activity more quickly at what temperature?

4C & 25C