Titration of human brain monoamine oxidase -A and -B by clorgyline and L-deprenil.
The interaction of clorgyline and L-deprenil with the -A and -B forms of human brain monoamine oxidase (MAO) has been studied. Both compounds inhibit cerebrocortical MAO in a manner consistent with a 'suicide' inactivation of the enzyme. The interaction of clorgyline with the -A form of the enzyme appears to take place almost entirely at specific binding sites, and the conditions required for this inhibitor to 'titrate' the concentrations of MAO-A have been elucidated. L-Deprenil has also been used to titrate the concentration of the -B form of MAO in cerebrocortical homogenates, but there is a considerable degree of non-specific binding of this compound. The two inhibitors have been used to titrate the concentrations of the two enzyme forms in frontal cortex homogenates from different age groups. There was a significantly higher MAO-B activity for the age range 73--95 years than for the age range 2--63 years. No significant differences between the two age groups were found for MAO-A. The activity of MAO-A in the samples correlated very well with the concentration of this enzyme form. Titration of the B-form of the enzyme with L-deprenil indicated an increased enzyme concentration with age, although other factors, such as the non-specific binding of this compound, could contribute to this effect.
D000328:Adult; D000368:Aged; D000375:Aging; D001596:Benzylamines / Q000378:metabolism; D001921:Brain / Q000201:enzymology*; D002540:Cerebral Cortex / Q000201:enzymology; D002675:Child, Preschool; D003010:Clorgyline; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D008995:Monoamine Oxidase / Q000032:analysis* / Q000145:classification; D009419:Nerve Tissue Proteins / Q000378:metabolism; D010627:Phenethylamines; D011437:Propylamines; D012642:Selegiline; D012701:Serotonin / Q000378:metabolism
D001596:Benzylamines; D009419:Nerve Tissue Proteins; D010627:Phenethylamines; D011437:Propylamines; D012642:Selegiline; D012701:Serotonin; D008995:Monoamine Oxidase; D003010:Clorgyline