Micelle enhanced spectrofluorimetric assay for laccase activity by a flow-injection stopped-flow technique

✍ Scribed by Houping Huang; Ruxiu Cai; Yumin Du; Zhixin Lin; Yun'e Zeng

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 490 KB
• Volume: 318
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/0003-2670(95)00442-4

✦ Synopsis

An automated flow-injection stopped-flow kinetic spectrofluorimetric method for determination of lactase activity is proposed. It is based on the oxidation of o-phenylenediamine

(1,Zdiaminobenzene) catalysed by lactase during the stopped-flow period, yielding 2,3-diaminophenazine, which is determined by a micelle enhanced spectrofluorimetric method in a non-ionic surfactant medium. The substrate solution with Brij-35 and the buffer with sample are pumped into the flow manifold at the same flow rate and merged in the flow cell, then stopped for measuring the fluorescence intensity (A,, = 425 nm, A,, = 530 nm) which increases with time, at a constant temperature of 46°C. The linear range of the method is 0.1-118 U 1-l with a detection limit of 0.07 U l-t, using a 5 mm stopped-flow reaction time. The proposed method has been applied to the assay for lactase activity of real samples at 10 samples per h.