Abstract
MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 277:285-290 (2004) - doi:10.3354/meps277285 Alkaline phosphatase activity in marine oligotrophic environments: implications of single-substrate addition assays for potential activity estimations Marta Sebastián1,*, F. Xavier Niell2 1Centro Oceanográfico de Málaga, Instituto Español de Oceanografía, PO Box 285, Fuengirola, Málaga, Spain 2Departamento de Ecologia, Facultad de Ciencias, Universidad de Málaga, 29071 Málaga, Spain *Email: marta.sebastian@ma.ieo.es ABSTRACT: Measurements of potential enzyme activities are usually carried out to compare enzymatic activity between different systems and minimise the effect of product inhibition or substrate depletion during the assay. There is a general practice of estimating potential alkaline phosphatase activity (APA) using single-substrate addition in excess of saturation, as complete kinetic experiments are time-consuming. Here, complete APA kinetic experiments were carried out in the Subtropical North Atlantic Ocean using from 0.1 to 100 µM concentration of the fluorogenic substrate MUF-P. There was a reduction of the velocity of reaction by excess of substrate in all experiments carried out (n = 7). This reduction could be related either to inhibition processes, to quenching effects, or to a loss of fluorescence of the product of reaction due to some kind of biological transformation. Moreover, the substrate concentration above which activity diminished was different between the cases studied. Therefore, there was only a narrow range of concentration in which single-substrate addition experiments would have given results comparable to the maximum enzyme activity, and this range differed between stations. Hence, in order to estimate APA potential activities in marine oligotrophic environments, complete kinetic experiments should be carried out, since the use of single additions in excess of substrate may give erroneous results. This conclusion may be extendable to other commonly performed assays of hydrolytic activities in aquatic environments that also use MUF-substrates. KEY WORDS: Alkaline phosphatase activity · Exoenzyme · Potential assays · Marine environments Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 277. Online publication date: August 16, 2004 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2004 Inter-Research.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
