A coupled assay for histidine decarboxylase: in vivo turnover of this enzyme in mouse brain
| Autor: | I. R. Smith, D. J. Keeling, Keith F. Tipton |
|---|---|
| Rok vydání: | 1984 |
| Předmět: |
Male
Carboxy-Lyases Mice Inbred Strains Histidine Decarboxylase Biology Mice chemistry.chemical_compound In vivo Animals Histidine Pharmacology chemistry.chemical_classification Chromatography Brain Substrate (chemistry) Rats Inbred Strains General Medicine Methylhistidines Histidine decarboxylase Enzyme assay Rats Enzyme chemistry Biochemistry biology.protein Histidine decarboxylase activity Histamine Half-Life |
| Zdroj: | Naunyn-Schmiedeberg's Archives of Pharmacology. 326:215-221 |
| ISSN: | 1432-1912 0028-1298 |
| DOI: | 10.1007/bf00505321 |
| Popis: | A sensitive coupled assay for histidine decarboxylase has been developed. This method involved conversion of [3H]histidine into [3H]histamine by the enzyme sample, with methylation of this product in situ, catalysed by the enzyme histamine N-methyltransferase, to yield [3H]N-tele-methylhistamine. The radioactive product was separated from the substrate by (i) extraction into chloroform, (ii) ion-exchange chromatography and (iii) liquid cation-exchange extraction. The "no tissue" assay blank comprised 0.0007% of the substrate radioactivity. Sample material with a histidine decarboxylase activity of as little as 0.14 fmol/min/ml (measured at 1 microM histidine) gave double the blank value. More than 50 assays could be performed in one day. This assay was used to determine the in vivo changes in mouse brain histidine decarboxylase activity following irreversible inhibition with (+) alpha-fluoromethylhistidine (alpha-FMH). From the time course of recovery of enzyme activity the half-life of histidine decarboxylase in vivo was calculated to be 53 h. |
| Databáze: | OpenAIRE |
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