Term
| Delta G (Gibb's Free Energy) |
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Definition
| Measures energy released or consumed in a reaction |
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Term
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Definition
Delta G less than 0.
Reaction is spontaneous
Reactants have more energy than products |
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Term
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Definition
Delta G is greater than 0
Reaction is not spontaneous
Reactants have less energy than products |
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Term
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Definition
| They lower the level of activation needed for a reaction to occur (do not alter delta G) |
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Term
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Definition
| Globular proteins that act as biological catalysts |
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Term
| Enzymes exhibit catalytic effect on substances known as what? |
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Definition
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Term
| Enzymes are ____ for substrate |
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Definition
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Term
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Definition
| The area in which the reaction of interest takes place on an enzyme |
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Term
| The enzyme remains what after the reaction? |
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Definition
| Unchanged (only things that change are substrates and product concentration) |
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Term
| The enzyme complex arranges the substrate in a way that |
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Definition
| Reduces the randomness of the reaction and thus lowers the internal rearrangements that allow the reaction to proceed |
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Term
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Definition
| Substrate fits into enzyme like lock and key |
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Term
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Definition
| Active site is not in the proper alignment until the substrates move in and form a conformational change |
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Term
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Definition
| Completely functional enzyme |
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Term
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Definition
| The protein portion of enzyme |
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Term
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Definition
Non protein portion of enzyme
Metallic elements that help activate enzyme (iron and zinc) |
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Term
| Holoenzyme is formed when what binds? |
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Definition
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Term
| Allosteric site of an enzyme |
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Definition
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Term
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Definition
| Vitamin-derived molecules who participate directly in the reaction (NAD and FAD) (Share electrons or protons, participates in redox reactions) |
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Term
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Definition
| A tightly-bound non-protein portion of the enzyme (Heme) |
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Term
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Definition
Bind to enzymes and allow them to function appropriately
Allows for conformational change so that the substrate can bind to the enzyme |
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Term
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Definition
Enzymes that differ in amino acid sequence but catalyze similar physiological reactions
Measured via immunoassay |
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Term
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Definition
| Enzymes that differ in monomeric units of quaternary structure |
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Term
| Factors that affect an enzyme |
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Definition
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Term
| Factors that affect the rate of enzyme-substrate binding |
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Definition
Concentration of enzyme
Concentration of substrate
Substrate specificity
Time
Inhibitors |
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Term
| Why is pH important in an enzymatic reaction? |
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Definition
| Several enzymes utilize cofactors that are ionizable and the pH affects the direction the reaction will proceed |
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Term
| Why is temperature important in an enzymatic reaction? |
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Definition
Temp impacts the kinetic energy that allows enzyme-substrate binding
Temp too low, less E-S binding and slower reaction rate. Temp too high, more E-S binding and a faster reaction rate |
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Term
| Enzyme nomenclature based on the original system |
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Definition
| Add the suffix -ase to the function |
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Term
| Enzyme nomenclature based on the IUPAC system |
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Definition
| Each enzyme is grouped into one of six categories |
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Term
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Definition
| Oxidoreductases (dehydrogenases, oxidases) |
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Term
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Definition
| Transferases (Transaminase, kinases) |
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Term
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Definition
| Hydrolases (Esterases, digestive enzymes) |
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Term
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Definition
| Isomerases (Phospho hexo isomerase, fumarase |
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Term
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Definition
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Term
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Definition
| Ligases or (Synthetases) (citric acid synthetase) |
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Term
| When given an IUPAC number |
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Definition
| The first number relates to category the enzyme falls in |
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Term
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Definition
| The reaction rate is measured and the effects of varying the conditions of the reaction is investigated |
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Term
| What two ways can enzyme kinetics be displayed graphically? |
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Definition
Michaelis-Menten Graph
Lineweaver-Burk Plot |
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Term
| Velocity on a Michaelis-Menten graph refers to what? |
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Definition
| Speed of product formation (Amount of product formed per time) |
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Term
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Definition
| Occurs when active site is saturated with substrate |
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Term
| Michaelis-Menten graph assumes that what remains constant? |
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Definition
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Term
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Definition
Substance concentration at 1/2 of Vmax
(Indicator of affinity) |
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Term
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Definition
| Velocity of product formation is based upon both enzyme concentration and substrate concentration |
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Term
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Definition
| Velocity of product formation is based on enzyme concentration |
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Term
| Which order of kinetics is preferable for clinical analysis and why? |
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Definition
| Zero order because substrate concentration will impact enzyme concentration. We only care about the enzyme |
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Term
| Equation used to determine velocity? |
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Definition
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Term
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Definition
| Velocity/rate of enzymatic activity |
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Term
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Definition
| The maximal rate of reaction when the enzyme is saturated. Goes up when velocity goes down |
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Term
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Definition
| The substrate concentration that produces 1/2 of the maximal velocity |
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Term
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Definition
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Term
| On a Michaelis-Menten graph where is First order kinetics? |
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Definition
| On the left side until the line evens out |
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Term
| On a Michaelis-Menten graph where is Zero order kinetics? |
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Definition
| On the left side of the graph once the reaction has reached Vmax and it can't take any more substrate |
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Term
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Definition
| Produces linear relationship and is easier for inhibitor identification |
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Term
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Definition
| Interact with the enzyme in such a way as to prevent it from working in a normal fashion |
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Term
| How are inhibitors different from denaturation? |
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Definition
| Denaturation involves destruction of structure of apoenzyme |
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Term
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Definition
| Reversible which include (competitive, non-competitive and uncompetitive) and Irreversible |
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Term
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Definition
| Bind to enzymes with non-covalent interactions and changes E-S complex formation |
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Term
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Definition
| The substrate and inhibitor can't bind to the enzyme at the same time |
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Term
| Non-competitive inhibitors |
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Definition
| The binding of the inhibitor to the enzyme reduces its activity but does not affect the binding of the substrate (Makes enzyme less efficient/slows enzyme down) |
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Term
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Definition
| Covalently modifies an enzyme (Covalent bond) |
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Term
| Competitive inhibitor graph |
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Definition
Km Increased
Affinity decreased |
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Term
| Noncompetitive inhibitor graph |
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Definition
Km remains constant
Vmax decreased |
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Term
| Uncompetitive inhibitor graph |
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Definition
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Term
| Enzymes found within the plasma are specific to what? |
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Definition
| A particular tissue or cell type (When damage happens to the cells, those specific enzymes get released into circulation. Looking at changes in enzyme concentration within the plasma can help identify a host of issues) |
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Term
| What do optimal enzyme conditions (when quantifying enzymes) assure |
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Definition
1. Rapid reaction for fast TAT
2. Sensitive to low enzyme concentrations |
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Term
| Increased enzyme concentrations will lead to |
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Definition
| faster product formation and substrate depletion |
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Term
| 4 ways to determine conc. of enzymes |
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Definition
Look for an increase in conc of product
Look for the change in conc of a coenzyme
Look for decrease in substrate conc
Coupled reactions |
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Term
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Definition
| Enzymes that can't be measured directly and need to use subsequent reactions to be measured. |
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Term
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Definition
Allow the reaction to move forward and only measure at one time point
Simpler methodology
Does not account for inhibitors that can prolong lag phase or activators that can speed up substrate depletion |
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Term
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Definition
Continuous monitoring, checking absorbance at varying intervals
(Find first three consistent delta abs and take the average of that) |
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Term
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Definition
The amount of enzyme that will catalyze a reaction with 1umol of substrate per minute/liter at a specified temp
(The units by which we express enzyme activity) |
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Term
| Calculation for enzyme concentration in international units |
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Definition
| (Delta Abs/min) x (10^6/(a)(b)) x (Total volume/ Sample volume) |
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Term
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Definition
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Term
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Definition
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Term
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Definition
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Term
| Enzyme concentration is directly proportional to changes in |
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Definition
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Term
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Definition
| (Delta Abs/min)/((Molar abs)x(Sample length)) |
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Term
| Kjeldahl reference method |
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Definition
| A total protein serum test used to detect nitrogen in proteins. (Not used in routine clinical lab) |
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Term
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Definition
| Formation of violet colored complex between copper sulfate and tripeptides (or more) in an alkaline medium. |
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Term
| What are some interferences of the Biuret method? |
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Definition
| Ammonium ions, bilirubin, hemoglobin, and lipemia. |
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Term
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Definition
| Most routinely analyzed specific protein often in conjunction with total protein. Influenced by hemoconcentration, posture, and age. |
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Term
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Definition
| Lipemia can interfere ifultracentrifugation isn't employed. |
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Term
| Lactate dehydrogenase (LD) (LDH) |
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Definition
| Found in liver tissue, skeletal muscle and heart (found in all tissue) |
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Term
| What are the isoenzymes of lactate dehydrogenase? |
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Definition
| Tetramer composed of H (heart) and M(muscle) |
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Term
| LD-1 (HHHH) isomer of lactate dehydrogenase |
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Definition
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Term
| LD-2 (HHHM) isomer of lactate dehydrogenase |
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Definition
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Term
| LD-3 (HHMM) isomer of lactate dehydrogenase |
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Definition
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Term
| LD-4 (HMMM) isomer of lactate dehydrogenase |
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Definition
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Term
| LD-5 (MMMM) isomer of lactate dehydrogenase |
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Definition
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Term
| LD-X (6) isomer of lactate dehydrogenase |
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Definition
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Term
| Total LD Clinical significance |
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Definition
| Liver disease, hemolytic anemia malignancy, leukemia |
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Term
| What type of indicator assay is used in LDH? |
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Definition
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Term
| Creatinine Kinase (CK) (CPK) |
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Definition
| Catalyzed the reversible transfer of phosphate group from ATP to creatine. Found in all types of muscle tissues |
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Term
| What are the isoenzymes of CK? |
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Definition
| Dimer composed of M(muscle and B(brain) |
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Term
| CK-1 (BB) isomer of creatine kinase |
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Definition
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Term
| CK-2 (MB) isomer of creatine kinase |
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Definition
| Heart and skeletal muscle (isoforms MB0, MB1 |
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Term
| CK-3 (MM) isomer of creatine kinase |
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Definition
| Skeletal muscle and heart (isoforms MM0, MM1 and MM2) |
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Term
| CK-Mt isomer of creatine kinase |
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Definition
| From the mitochondria, migrates cathodically to CK-3 |
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Term
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Definition
| Macromolecular forms associated with Igs and mitochondria CK |
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Term
| Clinical significance of CK: Total CK |
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Definition
| Tissue necrosis (muscle and heart) |
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Term
| Clinical significance of CK: CK-MB |
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Definition
| Myocardial infarction. Begins to rise within 4-6 hrs of onset of pain. Peaks @ about 24 hours. Returns normal within 48 hours |
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Term
| Clinical significance of CK: CK-MM |
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Definition
| AMI skeletal muscle diseases |
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Term
| Clinical significance of CK: CK-BB |
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Definition
| Brain tumor, stroke, cerebral trauma |
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Term
| What type of indicator assay is used in CK? |
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Definition
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Term
| Aspartate aminotransferase (AST) (GOT) |
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Definition
Catalyzes the reversible transfer of amino group from aspartate to a ketoacid.
Found in cell cytosol and mitochondria (highest conc in heart) |
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Term
| Clinical significance of AST: Acute myocardial infarction |
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Definition
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Term
| Clinical significance of AST: Hepatic disease |
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Definition
| Very high levels in parenchymal disease |
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Term
| Clinical significance of AST:Skeletal muscle |
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Definition
| Elecated in dieases where there is myositis or dystrophy |
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Term
| Clinical significance of AST:Pulomonary emboli |
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Definition
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Term
| Clinical significance of AST: Hemolytic disease |
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Definition
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Term
| Clinical significance of AST:Uremia |
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Definition
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Term
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Definition
Catalyzes the cleavage of phosphate from a phosphate ester at pH 10
Found in most organs of the body bound to cell membranes. Highest conc. in the liver, bone and intestine |
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Term
| Isoenzymes of ALP include |
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Definition
| Fast liver/liver/bone/intestine/placenta |
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Term
| What type of indicator assay is used in AST? |
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Definition
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Term
| What type of indicator assay is used in ALP? |
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Definition
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Term
| Clinical significance of ALP: Bone disease |
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Definition
| Increased when the osteoblastic activity is elevated |
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Term
| Clinical significance of ALP: Heptatic disease |
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Definition
| Increased in obstruction of bilary tree |
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Term
| Alanine aminotransferase (ALT) (GPT) |
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Definition
Catalyzes the reversible transfer of amino group from aspartate to a ketoacid.
Found in cell cytosol. Highest conc. in liver and kidney |
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Term
| What type of indicator assay is used in ALT? |
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Definition
| Measuring change in cofactors |
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Term
| Clinical significance of ALT? Hepatic disease |
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Definition
| Very high levels in parenchymal disease |
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Term
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Definition
Catalyzes the cleavage of phosphate ezter at pH<7
Found in the prostate, liver and spleen |
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Term
| What type of indicator assay is used in the ACP? |
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Definition
| Product formation (product changes color) |
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Term
| Clinical significance of ACP: Prostatic cancer |
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Definition
| Not used in screening, was replaced by PSA |
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Term
| Clinical significance of ACP: Bone disease |
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Definition
| Increased in Paget's disease |
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Term
| Clinical significance of ACP: Chronic Leukemia |
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Definition
| High bilirubin causes falsely low TRAP but not total ACP |
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