CC LEC 2 - Enzymes III Flashcards
Hydrolyzes the ester linkages of fats
(dietary triglycerides)alcohols & fatty acids
LPS
Major source of LPS
Pancreas
Isoenz of LPS
L1, L2, L3
most clinically significant &
sensitive LPS isoenz
L2
Detection almost only indicates acute pancreatitis
LPS
WHAT ENZ Intraabdominal conditions: Penetrating duodenal ulcers Perforatedpepticulcers Intestinal obstruction Acute cholecystitis
LPS
LPS activator
albumin/ionized calcium
LPS inhibitors
heavy metals (ex. quinine)
Substrate of turbidimetric and titrimetric LPS method
olive oil or triolein
LPS method
Simpler, more rapid
- Substrate: olive oil or triolein (more
used, pure form of triglycerides)
Turbidimetric Enzyme Reaction
LPS method - Estimate liberated fatty acids - Complicated because of lack of stable uniform substrates - Substrate: olive oil or triolein - Indicator reaction: Measures liberated fatty acids released by alkaline titration after 24 hours incubation
Cherry Crandall Method (Titrimetric)
Indicator of Cherry Crandall
phenolphthalein (salmon color)
indicator of sigma tiet
thymolphthalein
Oxidation of glucose-6-phosphate to
6- Phosphogluconate or corresponding
lactone
G6PD
Tissue sources: Adrenal cortex Spleen Thymus Lymph nodes Lactating mammary glands RBCs (little activity in normal serum)
G6PD
Maintain NADPH in reduced form
G6PD
? required to regenerate
sulfhydryl-containing proteins (ex.
glutathione) in its reduced state
NADPH
– protects
hemoglobin from oxidizing agents that may be present
Glutathione, reduced form
Deficiency is an inherited sex-linked trait & most common in African-Americans
G6PD
Only ? has different specimens depending on ↑/↓
G-6-PD
2 TYPES OF CHS
Pseudocholinesterase
True Cholinesterase
tissue sources type of CHS
Serum Pancreas Liver (main) Heart White matter of CNS
type of CHS
Muscle relaxant during surgery
Pseudochs
type of CHS Tissue sources: RBCs Nerve tissue/cells Brain
ACH/ True CHS
Hydrolyzes acetylcholine -> choline + acetic acid
For transmission of nerve impulses (acetylcholine is a major
neurotransmitter)
ACH/ True CHS
CHS methods
- Measures ↓ in pH resulting from the liberation of acetic acid
- Acid production
Michel Method (Electrometric Method)
CHS methods
- Measures the liberation of CO2 from the formation of acetic acid as acetylcholine is hydrolyzed
Manometric Method
CHS methods
- Most used
- Uses butylcholine (thiolester) as
substrate
Ellman Technique (Photometric Enzyme Reaction)
Hydrolysis of N-terminal residues from
certain peptides & amides containing free amino groups
Leucine aminopeptidase (LAP)
Tx sources
Urine, serum, bile
Leucine aminopeptidase (LAP)
Mtd for Leucine aminopeptidase (LAP)
Goldbarg and Rutenberg Method
Fluorochrome dyes for Goldbarg and Rutenberg Method
Acridine orange
Rhodamine
FITC (fluorescein isothiocyanate)
Reversible conversion of ornithine to
citrulline (synthesis of urea)
Ornithine Carbamoyl Transferase (OCT)
OCT tissue source
liver
Mtds for OCT (2)
- Reichard and Reichard Method
- Isotopic & microdiffusion technique - Colorimetric Method
Splitting of fructose-1,6-diphosphate to glyceraldehyde-3-phosphate & dihydroxyacetone phosphate
Aldolase
Tissue sources:
Widely distributed in all body cells
Prominent in skeletal muscles, heart
muscles, liver (most), & RBCs
Aldolase
-Important in the breakdown of glucose lactic acid (glycolytic breakdown)
Aldolase
Aldolase
Main tissue source: liver
B
Aldolase Same tissue sources as previous, but mainly found in the brain (hippocampus, Purkinje cells) - Catalyzes breakdown of alcohol
C
Aldolase Found in muscles, RBCs, kidneys, intestine, liver - Most in liver - Reacts with PLD2
A
