Enzymes Flashcards
are specific biologic proteins that catalyze biochemical reactions without altering the equilibrium point of the reaction or being consumed or changed in composition.
Enzymes
Found in all body tissues, frequently appear in the serum following cellular injury or, sometimes, in smaller amounts, from degraded cells.
Enzymes
Are often useful in the diagnosis of particular diseases or physiologic abnormalities.
Plasma/Serum Enzyme Levels
specific amino acid sequence
Primary structure
polypeptide chains twisting
secondary structure
structure with folding or bend
tertiary structure
If an enzyme contains more than one polypeptide unit
Quaternary structure
refers to the spatial relationships between the subunits.
Quaternary structure
interacts with particular charged amino acid residues.
Active site
may bond regulator molecules and, thereby, be significant to the basic enzyme structure.
Allosteric site
Different forms may be differentiated from each other based on certain physical properties:
- Electrophoretic mobility
- Solubility
- Resistance to inactivation.
results when an enzyme is subject to posttranslational modifications
Isoform
a nonprotein molecule; not an enzyme
Cofactor
Cofactor + Enzyme =?
Reaction
Nonprotein entities that must bind to particular enzymes ______ a reaction occurs
Before
is an organic compound (second substrates)
coenzymes
increasing its concentration will increases the velocity of an enzymatic reaction
Coenzymes
Example of coenzymes
NAD and NADP
are inorganic ions which alters the spatial configuration of the enzyme for proper substrate binding
Activators
Example of Activators
Calcium, Zinc, Chloride, Magnesium, and Potassium
are inorganic ion attached to a molecule
Metalloenzymes
Example of Metalloenzymes
Catalase and Cytochrome oxidase
Pancreas specific enzyme
Lipasa
A non-specific saliva and pancreas
Amylase
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
- 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:
- Impaired removal of enzyme form plasma
- Increased permeability of cell membrane
- Increased in the number of cells or production of cells
- Increased in the normal cell turnover
- Decreased clearance of enzymes
- Tissue necrosis and degradation
Catalyst, speeds up rnx, responsible for break down
Enzymes
