A screening system of prodrugs selective for MAO-A or MAO-B.
We synthesized several prodrugs of glycine and gamma-aminobutyric acid. In order to establish a screening system from the prodrugs of selective activity to MAO-A or MAO-B, we examined purification conditions such as solubilization with Triton X-100, precipitation with ammonium sulfate, gel filtration and anion exchange chromatography. MAO-B was purified from various tissues such as guinea pig brain, kidney and spleen. MAO-A from human placenta without MAO-B was unstable in above purifications and used as crude. At each purification step, we checked sensitivity of the enzyme to specific inhibitors by developing a convenient fluorescence assay, in which hydrogen peroxide produced by the enzyme was reacted with p-hydroxyphenylpropionic acid. A fluorescence microplate reader measured a fluorescence of the fluorescent product from p-hydroxyphenylpropionic acid with horseradish peroxidase. In comparison with milacemide, N,N-bis(carbamoylmethyl)-N-pentylamine was the best and exclusive substrate for MAO-B. 2-N-(phenylethylamino)-acetoamide was the good substrate for MAO-A and MAO-B same as milacemide. 4-N-(n-pentylamino)-butyric acid and 4-(N-phenylethylamino)-butyric acid were the moderate substrates for both enzymes, which should release gamma-aminobutyric acid. These drugs will be new leading compounds.
Matsukawa
Motomi
M
Faculty of Pharmaceutical Sciences, Setsunan University, 45-1 Nagaotogecho, Hirakata, Osaka, 573-0101, Japan.
Hirai
Toshikazu
T
Karita
Shoko
S
Akizawa
Toshifumi
T
Pan-Hou
Hidemitsu
H
Yoshioka
Masanori
M
Goto
Giichi
G
Parvez
Hasan
H
Youdim
Moussa B H
MB
D000818:Animals; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical / Q000379:methods; D005260:Female; D006168:Guinea Pigs; D006801:Humans; D008930:Mitochondria, Liver / Q000187:drug effects / Q000201:enzymology; D008995:Monoamine Oxidase / Q000378:metabolism*; D008996:Monoamine Oxidase Inhibitors / Q000032:analysis / Q000737:chemistry / Q000494:pharmacology*; D011355:Prodrugs / Q000032:analysis / Q000737:chemistry / Q000494:pharmacology*
D008996:Monoamine Oxidase Inhibitors; D011355:Prodrugs; D008995:Monoamine Oxidase