Please use this identifier to cite or link to this item: http://hdl.handle.net/10553/41907
Title: NADP+ -dependent isocitrate dehydrogenase activity in marine plankton
Authors: Tames-Espinosa, Mayte 
Martínez, Ico 
Romero-Kutzner, Vanesa 
Packard, Theodore T. 
Gómez, May 
Bondyale-Juez, Daniel R. 
UNESCO Clasification: 251001 Oceanografía biológica
Keywords: Carbon flux
NADP+-dependent isocitrate dehydrogenase
Plankton metabolism
Cellular respiration
Metabolic measurements
Marine ecology
Issue Date: 2018
Journal: Marine Chemistry 
Abstract: NADP+-isocitrate dehydrogenase (NADP-IDH), as one of the most active intracellular CO2-producing enzymes, was measured in marine plankton by adapting an enzyme assay to the 0.7–50 μm, 50–200 μm, and 200–2000 μm size fraction of the Canary Islands coastal plankton community. The variability of NADP-IDH activity in relation to pH, temperature, dilution of the sample, centrifugation or substrates was measured. In our hands, the maximum NADP-IDH activity (Vmax) in marine plankton samples was attained in 0.1 M phosphate buffer at pH 8.2 (pKa1 = 7.6 and pKa2 = 8.8), by adding 6 mM MgCl2, 0.3 mM NADP+ and 2 mM DL-trisodium isocitrate. The optimum temperature in these subtropic mesozooplankton samples was 28 °C, with an Arrhenius energy of activation (Ea) of 20.4 kcal mol−1 (85.4 J mol−1), and an Arrhenius collision frecuency factor (A) of 2.9·1011 mol NADPH s−1 (kg of protein)−1. The apparent Michaelis-Menten Km values for the substrates in crude homogenates at pH 8.5 and 18 °C were 271 ± 63 μM for isocitrate and 18 ± 3 μM for NADP+. This enzyme, in addition to its high CO2-producing activity, is also important in regulating other CO2-producing enzymes. Thus, it can be used to calculate: (1) respiration in marine samples; (2) carbon flux in the water column; (3) metabolic adaptations to environmental changes; (4) roles of the plankton components of the food chain; and (5) the reactive oxygen species (ROS) scavenging capacity of the marine plankton resources.
URI: http://hdl.handle.net/10553/41907
ISSN: 0304-4203
DOI: 10.1016/j.marchem.2018.06.003
Source: Marine Chemistry [ISSN 0304-4203], v. 204, p. 86-94
Appears in Collections:Artículos
Thumbnail
Preprint
Adobe PDF (2,21 MB)
Show full item record

SCOPUSTM   
Citations

2
checked on Apr 11, 2020

WEB OF SCIENCETM
Citations

1
checked on Feb 15, 2020

Page view(s)

31
checked on May 30, 2020

Download(s)

3
checked on May 30, 2020

Google ScholarTM

Check

Altmetric


Share



Export metadata



Items in accedaCRIS are protected by copyright, with all rights reserved, unless otherwise indicated.