INTRODUCTION Flashcards
Proteins produced by living cells that hastens chemical reactions in organic matter
Enzymes
They are measured in terms of their activity and not in terms of their absolute values
Enzymes
They frequently appear in the serum after cellular injury, degradation of cells or from storage areas
Enzymes
Nonprotein entities that must bind to particular enzymes before a reaction occurs
Cofactors
An organic compound(second substrates) increasing its concentration will increase the velocity of an enzymatic reaction
Coenzymes
It is essential to achieve absolute enzymatic activity
Coenzymes
Are inorganic ions which alters the spatial configuration of the enzyme for proper substrate binding
Activators
Are inorganic ions attached to a molecule
Metalloenzymes
Interferes with the reaction
Inhibitors
Physically binds to the active site of an enzyme
Competitive Inhibitor
Has the ability to alter the apparent Michaelis-Menten constant (Km)
Competitive Inhibitor
It looks for areas other than the active site
Non-Competitive Inhibitor
This inhibitor binds to the enzyme-substrate (ES) complex
Uncompetitive Inhibitor
These are enzymes having the same catalytic reactions but slightly different molecular structures
Isoenzymes
Enzymes are active at what temperature?
25℃, 30℃, or 37℃
The optimum temperature for enzymatic activity
37℃
The rate of denaturation increases as the temperature increases, and is usually significant at what temperature
40℃ to 50℃
Range of temperature that may result to inactivation of enzymes
60-65℃
Most physiologic reactions occur at what pH?
pH range of 7 to 8
May denature an enzyme or influence its ionic state resulting in structural change or change in the charge of amino acid residue in the active site
Extreme pH level
Render enzymes reversibly inactive
Low temperatures (Refrigeration/Freezing)
Denature proteins and should be avoided
Repeated freezing thawing
Required temp for preservation of enzymes for longer period of time
-20℃
Ideal storage temperature for substrate and coenzymes
2℃ to 8℃
Ideal storage for LDH (LD4 and LD5)
Room temperature
Mostly increases enzyme concentration
Hemolysis
Decreases enzyme concentration
Lactescense or Milky specimen
Part of the enzyme nomenclature that places the enzyme in its classifications
First digit
Represents the subclass to which the enzyme is assigned
Second and Third digits
Serial number that is specific to each enzyme
Final and fourth number/s
Classification of enzyme that catalyze the removal or addition of electrons (redox reaction)
Oxidoreductases
Enzyme classification that catalyze the transfer of a chemical group other than hydrogen from one substrate to another
Transferases
Enzyme classification that catalyze hydrolysis or splitting of a bond by the addition of water (hydrolytic reactions)
Hydrolases
Enzyme classification that catalyze removal of groups from substrates without hydrolysis. The product contains double bonds
Lyases
Enzyme classification that catalyze the intramolecular arrangement of the Substrate compound
Isomerases
Enzyme classification that catalyze the joining of two substrate molecules, coupled with breaking of pyrophosphate bond in ATP or similar compound
Ligases
General property of enzyme that is a water-free cavity, where the substrate interacts with particular charged amino acid residues; a 3-dimensional protein structure
Active site
A cavity other than the active site that may bind regulator molecules
Allosteric site
When bound tightly to the enzyme, the coenzyme is called what?
Prosthetic group
Apoenzyme + prosthetic group =
Holoenzyme
Digestive enzymes in its inactive form originally secreted from the organ of production is called
Proenzyme or zymogen
Theory that is based on the premise that the shape of the key (substrate) must fit into the lock (enzyme)
Emil Fisher’s Lock and Key Theory
Theory based on the substrate binding to the active site of the enzyme
Kochland’s Induced Fit Theory
An enzyme combines with only one substrate and catalyzes only one action
Absolute specificity
Enzymes combine with all the substrates in a chemical group
Group Specificity
Enzymes reacting with specific chemical bonds
Bond specificity
The reaction rate depends only on enzyme concentration
Zero-order reaction
The reaction rate is directly proportional to substrate concentration
First-order reaction
A general method where the reactants are combined, reaction proceeds for a designated time, the reaction is stopped and measurement is made
Fixed-Time
General method where multiple measurements of changed in absorbance are made during the reaction; it is preferred than fixed-time
Continuous monitoring/kinetic assay
