Enzymes Flashcards by Patricia Jill Cabison

are specific biologic proteins that catalyze biochemical reactions without altering the equilibrium point of the reaction or being consumed or changed in composition.

Enzymes

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Found in all body tissues, frequently appear in the serum following cellular injury or, sometimes, in smaller amounts, from degraded cells.

Enzymes

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Are often useful in the diagnosis of particular diseases or physiologic abnormalities.

Plasma/Serum Enzyme Levels

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specific amino acid sequence

Primary structure

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polypeptide chains twisting

secondary structure

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structure with folding or bend

tertiary structure

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If an enzyme contains more than one polypeptide unit

Quaternary structure

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refers to the spatial relationships between the subunits.

Quaternary structure

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interacts with particular charged amino acid residues.

Active site

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may bond regulator molecules and, thereby, be significant to the basic enzyme structure.

Allosteric site

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Different forms may be differentiated from each other based on certain physical properties:

Electrophoretic mobility
Solubility
Resistance to inactivation.

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results when an enzyme is subject to posttranslational modifications

Isoform

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a nonprotein molecule; not an enzyme

Cofactor

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Cofactor + Enzyme =?

Reaction

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Nonprotein entities that must bind to particular enzymes ______ a reaction occurs

Before

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is an organic compound (second substrates)

coenzymes

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increasing its concentration will increases the velocity of an enzymatic reaction

Coenzymes

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Example of coenzymes

NAD and NADP

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are inorganic ions which alters the spatial configuration of the enzyme for proper substrate binding

Activators

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Example of Activators

Calcium, Zinc, Chloride, Magnesium, and Potassium

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are inorganic ion attached to a molecule

Metalloenzymes

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Example of Metalloenzymes

Catalase and Cytochrome oxidase

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Pancreas specific enzyme

Lipasa

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A non-specific saliva and pancreas

Amylase

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This enzyme is elevated in alcoholic individual

Gamma Glutamyl Transferase (GGT)

This enzyme is associated with cellular injury

cytochrome P450

is an organic cofactor. Such as nicotinamide adenine dinucleotide (NAD)

Coenzyme

When bound tightly to the enzyme, the coenzyme is called a ______________

Prosthetic group

Another term for Prosthetic group

Apoenzyme

When a bound tightly to the enzyme, the coenzyme is a called a prosthetic group which forms a complete and active system

Holoenzyme

are originally secreted from the organ of production is a structurally inactive form.

Zymogen

Another term for Zymogen

Proenzyme

CoEnzyme + ApoE =?

HoloE

Cause of interference/stop/ prevent

Inhibitors

Binds to the active site of an enzyme and is reversible (Substrate > Inhibitor)

Competitive Inhibitor

Bind to the allosteric site (cofactor site) and is Irreversible

Noncompetitive Inhibitor

Binds to the enzyme-substrate complex (increased substrate is equal to increased enzyme-substrate complex is equal increased inhibition)

Uncompetitive Inhibitor

Same catalyctic reactions but slightly different molecular structures and involve in Fractionation of isoenzymes

Isoenzymes

Optimum temperature for enzymatic activity

37°C / body temp

increased temperature is equal to?

increased reaction | rate or increased movement of molecules

Denaturation of enzymes

40-50°C

Inactivation of enzymes

60-65°C

For every 10⁰C increase in temperature, there will be a two-fold increase in enzyme activity.

Temperature Coefficient

Most physiologic reactions occur in?

pH range of 7-8 (neutral to slightly alkaline)

Temperature for the storage of enzymes for longer periods of time

20°C

Temperature for storage for coenzymes

2-8°C

Temperature for storage for LDH (LDH 4 and 5)

Room Temp

Mostly increases enzyme concentration.

Hemolysis

Decreases enzyme concentration

Lactescence or milky specimen (CHYLE)

Test for rape victims

Acid Phosphatase (ACP)

In which body fluid is ACP found

Semen or in prostate (fluid)

Adopted classification system in

1961

Revision years

1972, 1978

Defines the substrate acted on.

Systemic ANme

are lengthy, a more usable and trivial.

Systemic Name

Assign by the IUB system

Recommended Name

System associated with ACE

Renin-Angiotensine-Aldosterone System

Catalyze an oxidation-reduction reaction between two substrates

Oxidoreductase

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

Transferases

Catalyze hydrolysis of various bonds

Hydrolases

Catalyze removal of groups from substrates without hydrolysis; the product contains double bonds

Lyases

Catalyze the interconversion of geometric, optical, or positional isomers

Isomerase

Catalyze the joining of two substrate molecules, coupled with breaking of the pyrophosphate bond in adenosine triphosphate (ATP) or a similar compound

Ligases

Enzymes included in Oxidoreductase

LDH, G-6-PDH, Glumate Dehydrogenase | HYDROGENASES

Enzymes included in Transferases

AST, ALT, GGT, Glutathione-S-Tranferase, Phosphorylase, Pyruvate kinase1 (PK) [TRANSFERASES, PHOSPHORYLASE, KINASE)

Enzymes in Hydrolases

Alkaline Phosphatase (ALP), ACP, α-Amylase (AMY), Cholinesterase (CHE, PCHE), Chymotrypsin (CHY), ELastase-1 (E1), 5-Nucleotidase (NTP), Triacyglyerol lipase (LPS), Trypsin (TRY)

Enzymes in Lyases

Aldolase (ALD)

Enzymes in Isomerases

Triphosphate isomerase (TPI)

Ligase

Glutathione Synthetase (GSH-S)

may occur spontaneously if the free energy or available kinetic energy is higher for the reactants than for the products

Chemical Reaction

also called excess energy

Activation Energy

Energy required to raise all molecules in 1 mol of a compound at a certain temperature to the transition state at the peak of the energy barrier.

Activation Energy

The general relationship among the enzyme, substrate, and product may be represented as follows:

E + S → ES → E + P

is a physical binding of a substrate to the active site of an enzyme.

Enzyme-Substrate Complex

combined with all substrates containing a particular chemical group, such as phosphate ester.

Group Specific

Enzymes that are specific to chemical bonds exhibits _________________.

Bond Specificity

refers to enzymes that predominantly combine with only one optical isomer of a certain compound

Stereoisometric Specificity

The rate at which an enzymatic reaction proceeds and whether the forward or reverse reaction occurs depend on several reaction conditions.

Substrate Concentration

One major influence on enzymatic reactions is________________.

Substrate Concentration

The reaction rate is directly proportional to substrate concentration

First-Order Kinetics

The reaction rate depends only on enzyme concentration

Zero-Order Kinetics

Shape of the key (substrate) must fit into the lock (enzyme)

Emil Fisher's/ Lock and Key Theory

Base on the substrate binding to the active site of the enzyme; Acceptable theory

Kochland/ Induced Fit Theory

Measurement of Enzyme Activity in terms of:

* Change in substrate concentration * Change in product concentration * Change in coenzyme concentration

Absorbance is made at 10-second intervals for 100 seconds

Nonkinetic Assay

To measure the extent of enzymatic reactions, 2 general methods may be used

1. Fixed-Time Assay | 2. Continuous monitoring/ Kinetic Assay

The reactants are combined; the reaction proceeds for a designated time; the reaction is stopped ad measurement is made.

Fixed Time Assay

Multiple measurements of changed in absorbance are made during the reaction; It is preferred than fixed-time

Continuous monitoring/ Kinetic assay

1 micromole of substrate/minute (MI-MI-U)

International Unit ( IU o U)

1 mole of substrate/second (MO-SE-KU)

Katal Unit (KU)

Quantified base one their activity rather than absolute values

Katal unit

The units used to report enzyme levels in kinetic assay are

activity units

The definition for activity unit must consider change in pH, temperature, substrate, etc.

Katal unit (KU)

Causes of Elevated Plasma Enzyme Levels:

1. Impaired removal of enzyme form plasma 2. Increased permeability of cell membrane 3. Increased in the number of cells or production of cells 4. Increased in the normal cell turnover 5. Decreased clearance of enzymes 6. Tissue necrosis and degradation

Catalyst, speeds up rnx, responsible for break down

Enzymes

Enzymes Flashcards

(95 cards)