Rapid and simple measurement of serotonin N-acetyltransferase activity by liquid biphasic diffusion assay.
We report here a rapid, simple, and accurate method to assay for serotonin N-acetyltransferase (NAT) activity. This assay relies on the selective diffusion of radiolabeled acetyltryptamine into a water-immiscible scintillation fluid. Unlike organic solvent extraction, thin-layer chromatography, or high performance liquid chromatography, the separation of acetyltryptamine from acetyl CoA and tryptamine is not required in the method. Moreover, the limit of sensitivity is less than 4 pmol of N-acetyltryptamine formed per sample. Enhancement of NAT activity upon beta-adrenergic receptor stimulation in the rat pineal gland was clearly detected with this method. In addition, the NAT activity measurements obtained with this method agreed quantitatively in the pineal gland and other brain tissues with the conventional organic solvent extraction method. The results suggest that this liquid biphasic diffusion assay is applicable to the detection of NAT activity in tissues and cells.
Chae
H D
HD
Department of Life Science, Pohang University of Science and Technology, South Korea.
Park
T J
TJ
Lee
Y K
YK
Lee
T G
TG
Kim
K T
KT
D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000818:Animals; D001191:Arylamine N-Acetyltransferase / Q000032:analysis*; D004058:Diffusion; D008297:Male; D008550:Melatonin / Q000096:biosynthesis; D009419:Nerve Tissue Proteins / Q000032:analysis*; D009924:Organ Culture Techniques; D010870:Pineal Gland / Q000187:drug effects / Q000201:enzymology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011943:Receptors, Adrenergic, beta / Q000502:physiology; D012588:Scintillation Counting; D012680:Sensitivity and Specificity; D012995:Solubility; D012997:Solvents; D014363:Tryptamines / Q000032:analysis / Q000096:biosynthesis; D014867:Water
D000318:Adrenergic beta-Agonists; D009419:Nerve Tissue Proteins; D011943:Receptors, Adrenergic, beta; D012997:Solvents; D014363:Tryptamines; D014867:Water; C043464:N-acetyltryptamine; D001191:Arylamine N-Acetyltransferase; D008550:Melatonin