Ch. 13 - Enzymes (CHS - ALS) (RVSP) Flashcards
2 types of CHS
- Pseudocholinesterase (PChe)/acylcholine acylhydrolase
- True cholinesterase/Acetylcholinesterase (AChe)
Enzyme class of Cholinesterase (CHS)
Hydrolase
Tissue sources of pseudocholinesterase
Liver (main) Pancreas Serum Heart White matter of CNS
CHS type as muscle relaxant in surgery
Pseudocholinesterase
Tissue sources of Acetylcholinesterase
RBCs
Nerve tissue/cells
Brain
Enzyme for transmission of nerve impulses
Acetylcholinesterase
Rxn equation of acetylcholinesterase
Acetylcholine –acetylcholinesterase–> choline + acetic acid
Conditions of decreased levels of acetylcholinesterase
Parenchymatous liver diseases Insecticide poisoning (organophosphorous) Metastatic carcinoma Malnutrition Anesthetic overdose Heart failure Acute infection
3 mtds for CHS
Michel mtd (Electrometric mtd) Manometric mtd Ellman Technique (Photometric Enzyme Reaction)
CHS mtd; measures decrease in pH resulting from liberation of acetic acid
Michel Mtd (Electrometric mtd)
CHS mtd; measures the liberation of CO2 from the formation of acetic acid as acetylcholine is hydrolyzed
Manometric mtd
Substrate used in Ellman technique for CHS
Butylcholine (thiolester)
Most used mtd for CHS
Ellman technique (Photometric Enzyme Reaction)
Wavelength in Ellman Technique for CHS
410 nm
Rxn equation in Ellman technique for CHS
Butylcholine + DTNB –> 5-MNBA
DTNB
5,5’-dithiobis-2-nitrobenzoic acid
MNBA
5-monothio-nitrobenzoic acid
Enzyme class of leucine aminopeptidase (LAP)
Hydrolase
Enzyme for hydrolysis of N-terminal residues from certain peptides & amides containing free amino groups
LAP
Tissue sources of LAP
Bile
Urine
Serum
Conditions of increased levels of LAP
Pancreatitis Hepatobiliary diseases (hepatitis & cirrhosis) Obstructive jaundice Metastatic carcinoma of the liver
Mtd for LAP
Goldbarg and Rutenberg Mtd
Characteristics of the Goldbarg and Rutenberg mtd for LAP
Fluorometric
Colorimetric
Fluorochrome dyes used in the Goldbarg and Rutenberg mtd for LAP
- FITC (flourescein isothiocyanate)
- acridine orange
- rhodamine
Enzyme class of Ornithine Carbamoyl Transferase (OCT)
Transferase
Tissue source OCT
Liver
Enzyme for the reversible conversion of ornithine –> citrulline (synthesis of urea)
Ornithine carbamoyl transferase (OCT)
Conditions of increased levels of OCT
- cirrhosis
- heart failure
- acute viral hepatitis
- metastatic carcinoma (slight increase)
- delirium tremens
- obstructive jaundice
- cholecystitis
2 mtds for OCT
- Reichard and Reichard Mtd
- Colorimetric mtd
Isotopic and microdiffusion technique for OCT
Reichard and Reichard Mtd
Other name for the Reichard and Reichard mtd for OCT
Isotopic and Microdiffusion technique
Most commonly requested enzyme in the lab
Aldolase (ALS)
Enzyme class of aldolase (ALS)
Lyase
Rxn equation of ALS
Fructose-1,6-diphosphate –ALS–> glyceraldehyde-3-phosphate + dihydroxyacetone phosphate
Enzyme important in the breakdown of glucose to lactic acid (glycolytic breakdown)
ALS
Tissue sources of ALS
- liver (most)
- Skeletal muscles
- heart muscles
- RBCs
Isoenzymes of ALS
Isoenzyme A
Isoenzyme B
Isoenzyme C
Tissue sources of ALS Isoenzyme A
- Liver (most)
- RBCs
- kidneys
- intestine
- muscles
Substance that reacts with ALS Isoenzyme A
PLD2
Main tissue source of ALS Isoenzyme B
Liver
Main tissue source of ALS Isoenzyme C
Brain (hippocampus and Purkinje cells)
ALS isoenzyme that catalyzes the breakdown of alcohol
Isoenzyme C
Conditions of increased levels of ALS
- progressive muscular dystrophy
- inflammatory muscle disease
- liver diseases/necrosis
- MI
- Pulmonary infarction
- malignancy
- megaloblastic anemia
Principle for ALS mtds
Rate at which thioses are formed/rate at which dinitrophenylhydrazone is formed
