30 Questions
What is the main purpose of determining enzyme activities in plasma?
To diagnose diseases of the heart and liver
Which of the following enzymes is not an example of an intracellular enzyme?
Prothrombin
What happens to enzyme levels in plasma when there is tissue damage?
Enzyme levels increase
What is the term for the use of enzymes as therapeutic agents?
Enzymotherapy
Which of the following enzymes is specific to the pancreas?
Amylase
What is the possible cause of increased plasma levels of ALT?
Hepatitis
What is the term for the enzymes produced by tissues and acting in plasma?
Secretory enzymes
Which enzyme is commonly assayed to diagnose prostatic cancer?
Acid phosphatase
What is the effect of cell necrosis on plasma enzyme levels?
Release of membrane-bound enzymes
What is the purpose of determining reference values of enzyme activities?
To establish a baseline for healthy individuals
Why do healthy individuals have low levels of intracellular enzymes in plasma?
Because the rate of enzyme release from damaged cells is balanced by the rate of removal of enzyme from plasma
Which of the following is an isoenzyme of creatine kinase?
CK-MM
What is the possible cause of increased plasma levels of ALP?
Rickets
What is the therapeutic use of digestive enzymes?
Substitution of missing production of digestive enzymes
Which enzyme is commonly assayed to diagnose acute pancreatitis?
Amylase
What is the effect of disturbances of energy metabolism on enzyme plasma levels?
Release of cytosolic enzymes
What is the function of ATP, ADP, and AMP in the cell?
Energy transport
What is the name of the enzyme-linked immunoadsorbent assay?
ELISA
What is the role of cAMP in the cell?
Intracellular mediator, second messenger of hormonal signal transduction
What is the nitrogenous base in ATP?
Adenine
What is the function of NAD+, NADP+, and FAD?
Coenzymes
What is the sugar molecule in ATP?
Ribose
What is the mechanism of action of cAMP?
Allosteric effector
What is the function of nucleotides in DNA and RNA synthesis?
Precursors of DNA, RNA
What is the main purpose of enzyme therapy in treating various diseases?
To treat skin defects and digestive disorders
Which of the following enzymes is used to treat embolization in the lungs?
Streptokinase
What is the name of the mixture of pancreatic and plant proteolytic enzymes used to treat inflammatory diseases?
Wobenzym
Which of the following is NOT a use of enzymes in laboratory assays?
Treating skin defects
What is the main advantage of enzyme methods over chemical methods in laboratory assays?
They are more specific
Which of the following enzymes is used to determine the presence of urea in blood?
Urease
Study Notes
Nucleotide Structure
- A nucleotide consists of a nitrogenous base, a pentose sugar, and one or more phosphate groups
- Types of nitrogenous bases: purine (e.g., adenine) and pyrimidine (e.g., nicotinamide)
- Types of pentose sugars: ribose and deoxyribose
Nucleosides and Nucleotides
- Adenosine triphosphate (ATP) is a nucleotide with adenine as the nitrogenous base, ribose as the pentose sugar, and a phosphate chain
- ATP has three phosphate groups, which can be broken down to release energy
- Adenosine monophosphate (AMP) and adenosine diphosphate (ADP) are other nucleotides with one and two phosphate groups, respectively
- Cyclic adenosine monophosphate (cAMP) is a nucleotide with a cyclical phosphate group, acting as an intracellular mediator and second messenger in hormonal signal transduction
Nucleotide Functions
- Precursors of DNA and RNA
- Energy transport: ATP, ADP, and AMP
- Allosteric effectors of enzymes: binding to the site of an allosteric enzyme, causing a change in configuration and affecting enzyme activity
- Intracellular mediators (second messengers): cAMP and cGMP
- Coenzymes: NAD+, NADP+, and FAD
Enzymes in Medicine
- Diagnostic indicators: measuring enzyme activities in plasma for diagnostic purposes in diseases of the heart, liver, skeletal muscle, pancreas, and other tissues
- Therapeutic agents: using enzymes as drugs (enzymotherapy)
- Diagnostic tools: using enzymes in clinical laboratory assays
Enzymes in Clinical Diagnosis
- Secretory enzymes: produced by tissues, acting in plasma (e.g., prothrombin, plasminogen, ceruloplasmin, choline esterase, and lipoprotein lipase)
- Intracellular enzymes: have no physiological use in plasma, but can be used as diagnostic indicators (e.g., ALP, ALT, AST, and LD)
- Tissue-specific enzymes: glucose-6-phosphatase in liver, amylase in pancreas, and LD1 in heart
Alteration of Enzyme Plasma Levels
- Elevated enzyme activity in plasma can indicate tissue damage or cell necrosis
- Increased cell membrane permeability or induction of enzyme synthesis can also cause elevated enzyme levels
- Decreased enzyme activity can be due to inhibition of enzyme synthesis or activity
Enzymes in Therapy
- Substitution of missing digestive enzymes: using pepsin, trypsin, and other enzymes to treat digestive disorders
- Removal of dead tissue or fibrin: using proteinases, nucleases, and collagenase to treat skin defects and lung embolization
- Acceleration of fibrinolysis: using streptokinase and urokinase to treat lung embolization
Enzymotherapy
- Orally administered enzymes: using mixtures of plant and/or animal origin enzymes to treat digestive, gastrointestinal, and pancreatic disorders
- Examples of enzymotherapy: pancreatin (trypsin, chymotrypsin, lipase, and amylase) and Wobenzym (pancreatic and plant proteolytic enzymes)
Enzymes in Laboratory Assays
- Enzymes isolated from different sources are used for determination of various substances in blood, plasma/serum, and urine
- Enzyme methods are more specific than chemical methods and are not affected by the presence of relative substances with similar chemical properties
This quiz covers the composition of nucleotides, types of nitrogenous bases, and pentose sugars. It also touches on ATP and its phosphate groups.
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