CK LDH GGT G6PD ACE 5N’T CHE AChE PChE ALD Flashcards
E.C. 2.7.3.2
Creatine Kinase
MW of CK
82,000 Da
Associated with AT Pregeneration in contractile or
transport system (constant concentration of ATP in the muscle needed for any sudden burst of exercise)
Creatine Kinase
CK
Isoenzymes, Tissue Sources, and Electrophoresis
CK-MM = Skeletal Muscle (CK-3)
CK-MB = Heart muscle (CK-2)
CK-BB = Brain tissues (CK-1)
CK isoenzyme that migrate fastest toward anode
CK-BB
CK isoenzyme that exhibit slowest mobilty
CK-MM
Most significant CK
CK-MB
CK-MB Myocardial Infarction: Rise
4-8 hours after the onset
CK-MB Myocardial Infarction: Peak
12-24 hours
CK-MB Myocardial Infarction: return to normal
Within 48-72 hours
T or F
CK-MB is specific to MI
False; CK-MB is SENSITIVE but NOT specific to MI
ATYPICAL ISOENZYMES
Bound to the exterior surface of inner mitochondrial membranes of muscle, brain, and liver.
CK-Mi (Mitochondrial Creatine Kinase)
CK-Mi
For it to be detected in PLASMA, ? must occur, causing breakdown of the mitochondria and cell wall
Extensive tissue damage
In most instances, the associated immunoglobin in Macro-CK
IgG
Largely comprises CK-BB complexed with IgG
Macro-CK
LDH EC
EC 1.1.1.27
Systematic name of LDH
L-Lactate: NAD+ Oxidoreductase
Catalyzes the interconversion of lactate to pyruvate;
Pyruvate to lactate in anaerobic glycolysis
LDH
Reaction of LDH in anaerobin glycolysis
Pyruvate -> lactate
LDH Higher Activities are found in
HELiSK
Heart
Erythrocytes
Liver
Skeletal muscle
Kidney
LDH lesser amounts found in the
Lung
Smooth Muscle
Brain
ISOENZYMES - TISSUE LOCALIZATION AND SOURCES OF ELEVATION
LDH-1 (HHHH)
Heart - Myocardial Infarction
Red Blood cell - Hemolytic anemia
ISOENZYMES - TISSUE LOCALIZATION AND SOURCES OF ELEVATION
LDH-2 (HHHM)
Heart - Megaloblastic anemia
RBC - Acute Renal Infarction, Hemolyzed Specimen
ISOENZYMES - TISSUE LOCALIZATION AND SOURCES OF ELEVATION
LDH-3 (HHMM)
Lung - Pulmonary Embolism
Lymphocytes - Extensive Pulmonary Pneumonia
Spleen - Pulmonary Pneumonia
Pancreas - Lymphocytosis, Acute Pancreatisis
ISOENZYMES - TISSUE LOCALIZATION AND SOURCES OF ELEVATION
LDH-4 (HMMM)
Liver - Hepatic injury or inflammation
ISOENZYMES - TISSUE LOCALIZATION AND SOURCES OF ELEVATION
LDH-5 (MMMM)
Skeletal muscle - Skeletal muscle injury
LDH Myocardial Infarction: Rise
12-24 hours after the onset
LDH Myocardial Infarction:Peak
48-72 hours
LDH Myocardial Infarction: Remain elevated
10 days
LD pattern suggestive of AMI
LD1>LD2>LD3>LD4>LD5
EC of Gamma-Glutamyl-Transferase
E.C. 2.3.2.2.
GGT Systemic name
(5-Glutamyl) Peptide: Amino Acid-5-Glutamyl-Transferase
GGT is Involved in the transfer of the gamma-glutamyl residue from gamma-glutamyl peptides to -, - and other small peptides
amino acid, H2O
Glutathione is a tripeptide composed of -, -, and -
Glutamate
Cysteine
Glycine
GGT physiology
- Involved in peptide and protein synthesis
- regulation of tissue glutathione levels
- transport of amino acids across cell membrane
GGT highest concentration tissue source
kidney
GGT other tissue sources
- brain
- prostate
- pancreas
- liver
clinical applications of GGT assay; primary sources of plasma GGT
evaluation liver and biliary system disorders
GGT is increased/elevated in
- elevated in all HEPATOBILLIARY DISODERS
- increased in patients receiving ENZYME-INDUCING DRUGS
- increased in CHRONIC ALCOHOLISM/Excessive alcohol consumption
enzyme-inducing drugs that will cause an elevated GGT
warfarin
phenobarbital
phenytoin
GGT
bone disease and biliary obstuction
Normal in BD
increased in BO
ALP
bone disease and biliary obstruction
all increase
Assay used in measuring Gamma-Glutamyl Transferase
Szasz assay
? And ? are located in the canalicular end, both of them are present in hepatobiliary conditions.
GGT and ALP
Substrate used for Szasz assay
Gamma-glutamyl-p-nitroanilide
szasz assay
? Is measured because its formation depends on the GGT
Para-Nitroaniline
yellow chromogenic product with a strong absorbance at 405 to 420 nm
Para-nitroaniline
EC for G6PD
1.1.1.49
G6PD systematic name
D-Glucose-6-Phosphate: NADP+ 1-Oxidoreductase
Catalyzes the oxidation of glucose-6-phosphate to 6-phosphogluconate or 6-phosphogluconolactone
Glucose-6-phosphate dehydrogenase (G6PD)
Lactate Dehydrogenase Coenzyme
Nicotinamide Adenine Dinucleotide NAD+
The conversion of glucose-6-phosphate to 6-phosphogluconate will also produce
NADPH
Diagnostic Significance of G6PD: RBC
- maintain NADPH in reduced form
- require reduced NADPH to reduce glutathione
- reduced glutathione protects hemoglobin (Hgb) from oxidation
Low G6PD may cause
Low NADPH = low reduced glutathione = hemolytic anemia
? must be present for anemia to occur in patients with G6PD
deficiency.
Oxidative stress
G6PD deficiency assay
Red cell hemolysate
G6PD
? Is used for evaluation of enzyme elevations
Serum
used as a confirmatory test for G6PD
Hemolysate
EC for ACE
3.4.15.1
ACE converts ? To ?
Angiotensin1 to Angiotensin 2
Other names for ACE
Kininase II and Peptidyl-Dipeptidase A
Hydrolysis of peptide bonds at a free C-terminus
releasing a dipeptide in the reaction
G6OD
ACE will Cleave ? In Angiotensin 1 to form Angiotensin 2
His-Leu sequence (Histidine-Leucine)
ACE contains ? In its active site
Zinc
Produces angiotensinogen
Liver
Produces renin
Kidney
Renin and angiotensinogen are activated by ?
Low blood pressure
Converts angiotensinogen to angiotensin 1
Renin
Cleaves the angiotensin seq to form angiotensin 2
ACE from the lungs
Effects of Angiotensin 2
Induce waterabsorption
Aldosterone = high blood pressure due to absorbed sodium
Endpoint of ACE
Higher blood pressure
Angiotensinogen converting enzyme inhibitors used for patients w high blood pressure
Captopril
ACE is predominantly found in ?
Endothelial cell membranes
Rich in ACE
Lungs
Testes
Substrate used to assess ACE levels
Hippurif acid
Hippuric acid is composed of
Hippuric acid
Histidine
Leucine
Abnormal collection of inflammatory cells called granulomas
may appear on the body (overreaction of the immune system)
Sarcoidosis
Sarcoidosis mainly affect the ?
Lungs
Most commonly affected areas of Sarcoidosis
Lungs
Skin
Eyes
Lymph nodes
ACE level: ?
Sarcoidosis progress to fibrosis
Decline
ACE is elevated w what illness
Sarcoidosis (Pulmonary involvement)
Granulomatous disease (10%)
EC OF 5’-Nucleotidase (5’NT)
EC 3.1.3.5
MW of 5’NT
70 kDa
It is a cytoplasmic membrane–bound phosphatase with a wide
specificity for 5′-ribonucleotides
5’-Nucleotidase
5’-Nucleotidase function in
Adenosine production
Nutrient absorption
Cell proliferation
5’-Nucleotidase acts only on - ?; substrate
Nucleotides (adenosine 5’-monophosphate and guanosine 5’-monophosphate)
Function of 5’NT
Nucleotide will be converted into RIBONUCLEOSIDE = release PHOSPHATE GROUP
5’NT systematic name
5’-Ribonucleotide Phosphohydrolase
5NT is widely distributed in ?
Tissues
5NT clnical uyilit is the diagnosis of ?
hepatobiliary disorders
5’NT serves as a marker to differentiate between ? and ?
Bone
Liver alkaline phosphatase
capable of cleaving the substrate used to measure the lower activity of 5′-NT present in the sample.
ALP
5’NT
High concentrations of nonspecific phosphatases may cause
Falsely increased results
inhibit 5’NT enzyme activity, likely due to the chelation of zinc
EDTA
Samples used for 5’NT
Serum
EC of Acetylcholinesterase
EC 3.1.1.7
EC of Pseudocholinesterase (PChE)
EC 3.1.1.8
True’ cholinesterase (choline esterase 1) or RBC cholinesterase
Acetylcholinesterase (AChE)
Butyrylcholinesterase (choline esterase 2)
Pseudocholinesterase (PChE)
AChE is found in the
Nervous system
Neuromuscular junctions
RBCs
primary neurotransmitter at various sites in the CNS
AChE
AChe rapidly hydrolyzes ?, producing rapid termination of neurotransmission
ACh (Acetycholine)
ACh is produced from
Choline
Acetyl CoA
serves as a neurotransmitter for signal transmission.
ACh
transported back into the axon terminal for ACh
synthesis.
Choline
ACh is broken down by acetycholinesterase into
Acetate and choline
Prolonged presence of ACh in the synaptic cleft can lead to
excessive signal transmission and paralysis
Main reason for measuring AChE
- to monitor EXPOSURE to
cholinesterase inhibitors - for use as a LIVER FUNCTION TESTS
- for DIAGNOSIS of genetic variants
Useful in organophosphate exposure and poisoning
Ache
prevents the breakdown of acetylcholine (ACh)
organophosphates insectisides
have the capability to inhibit cholinesterase (ChE)
Snake toxins
reflects acute toxicity
PChe
reflects chronic exposure.
AChE
indicates toxic exposure
Low level of cholinesterase
may be useful in the diagnosis of neural tube defects
Qualitative analysis in amniotic fluid
PChe is produced by the
Liver
Function of PChe
Not known
Pche is also called
Acetylcholine acylhydrolase
neuromuscular blocking agent, and muscle relaxants used during surgery
Succinylcholine
Mivacurium
important in the cleavage of acetylcholine antagonists such as succinylcholine and mivacurium
PCHE
Irreversible inhibitors of both AChE and PChE; unable to break down ACh
Organophosphate Insecticides
Substrate used to react w ACHe and PCHe to produce thiocholine
Acylthiocholine ester
Reacts w Ellman’s reagent (dithiobisnitrobenzoicacid), releasing 5-mercapto-2-nitrobenzoic acid
Thiocholine
Thiocholine is then reacted with Ellman’s reagent
(dithiobisnitrobenzoicacid), releasing ?
5-mercapto-2- nitrobenzoic acid
Ellman’s reagent
Dithiobisnitrobenzoic acid
5-mercapto-2- nitrobenzoic acid, which is measured spectrophotometrically at
412 nm
Pseudocholinesterase activity is measured in ?
Serum
AChE activity is measured in
Hemolysate of washed RBCs
AChE may also be determined in AMNIOTIC FLUID by ?
Gel electrophoresis
AChe in amniotic fluid may be useful in the diagnosis of ?
Neural tube defects and other birth defects
a condition when a baby’s SPINE and SPINAL CORD does not develop properly in the womb, causing a GAP in the spine.
Spina bifida
a serious birth defect in which a baby is born WITHOUT parts of the BRAIN and SKULL.
Anencephaly
a sac-like protrusion or projection of the brain and the membranes that cover it through an opening in the skull.
Encephalocele
EC of aldolase
EC 4.1.2.13
Aldolase systematic name
D-fructose- 1,6 - bisphosphate- D-Glyceraldehyde - 3 - phosphate - lyase
catalyzes the REVERSIBLE conversion of fructose-1,6-bisphosphate to glyceraldehyde 3-phosphate (G3P) and dihydroxyacetone phosphate (DHAP)
ALD
Aldolase A tissue source
Skeletal muscle
Aldolase B tissue source
WBC, Liver, Kidneys
Aldolase C tissue source
Brain tissue