Quantitation of human MAO A and B in liver, intestine and placenta: Reassessment of activity
Monoamine oxidases (MAO) oxidize a variety of exogenous and endogenous amines including neurotransmitters such as serotonin, dopamine and norepinephrine as well as the potent dopaminergic neurotoxin 1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine (MPTP). The two forms of MAO (A and B) differ in molecular weight and inhibitor selectivity, and are differentially expressed in the nervous system and many other tissues. Although some substrates are preferentially oxidized by one form of MAO, substrates that can be oxidized by only one MAO form have not been reported. How well each MAO oxidizes various substrates has not been thoroughly characterized because of difficulties in separating and quantitating MAO A and B active sites. By immunoblotting SDS-polyacrylamide gels of mitochondrial extracts with monoclonal antibodies specific for each form of MAO, MAO B protein was detected in intestine and placenta, tissues that have been reported to contain MAO A activity. An improved procedure was developed for quantitating the ratio and amounts of MAO A and B active sites, using the ligand ({sup 3}H)-pargyline to label MAO and specific monoclonal antibodies to separate MAO A from B. Data from liver, placenta and platelets were used to re-evaluate the molecular activity of both MAO A and B for six commonly studied substrates.
- Research Organization:
- Texas Univ., Galveston, TX (USA)
- OSTI ID:
- 6705292
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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AMINE OXIDASES
ENZYME ACTIVITY
ELECTROPHORESIS
INTESTINES
LIVER
MAN
MITOCHONDRIA
MOLECULAR WEIGHT
MONOCLONAL ANTIBODIES
PLACENTA
SUBSTRATES
TISSUE DISTRIBUTION
TRACER TECHNIQUES
TRITIUM COMPOUNDS
ANIMALS
ANTIBODIES
BODY
CELL CONSTITUENTS
DIGESTIVE SYSTEM
DISTRIBUTION
ENZYMES
FETAL MEMBRANES
GASTROINTESTINAL TRACT
GLANDS
HYDROGEN COMPOUNDS
ISOTOPE APPLICATIONS
MAMMALS
MEMBRANES
ORGANOIDS
ORGANS
OXIDOREDUCTASES
PRIMATES
VERTEBRATES
550201* - Biochemistry- Tracer Techniques