Measurement of ATP citrate-lyase and acetyl-CoA synthetase activity using arylamine acetyltransferase

✍ Scribed by Georg Hoffmann; Ludwig Weiss; Otto H. Wieland

• Publisher: Elsevier Science
• Year: 1978
• Tongue: English
• Weight: 456 KB
• Volume: 84
• Category: Article
• ISSN: 0003-2697
• DOI: 10.1016/0003-2697(78)90062-3

✦ Synopsis

Methods are described for the assay of ATP citrate (pro-3S)-lyase (EC 4.1.3.8) and acetyl-CoA synthetase (EC 6.2.1.1) activity in crude tissue extracts. Arylamine acetyltransferase (EC 2.3.1.5) and p-nitroaniline serve as indicator system in these tests. The methods have several advantages with respect to other optical enzyme assays. They are more sensitive than NADH-or hydroxylaminedependent methods due to the higher molar extinction coefficient of p-nitroaniline, which was redetermined under assay conditions. The assay is independent of nonspecific "NADH oxidase" activity. Continuous readings of the optical density can be performed. Specific activities of ATP citrate-lyase and acetyl-CoA synthetase have been measured in livers of starved and refed rats. Carbohydraterich refeeding leads to an increase in both enzyme activities. A modification of the biuret method for the use in lipid-rich tissue extracts is described.