The SR Ca[sup 2+] ATPase of the Antarctic scallop Adamussium colbecki: Cold adaptation and heavy metal effects
- Univ. del Piemonte Orientale, Alessandria (Italy). Dipt. di Scienze e Tecnologie Avanzate
- Univ. de Genova, Genoa (Italy)
Cell calcium is accumulated in intracellular stores by sarco-endoplasmic reticulum Ca[sup 2+] ATPases functionally interacting with the membrane lipid environment. Cold adaptations of membrane lipids in Antarctic Sea organisms suggest possible adaptive effects also on sarco-endoplasmic reticulum Ca[sup 2+] ATPases. The authors investigated the SR Ca[sup 2+] ATPase of an Antarctic scallop, Adamussium colbecki, by characterizing the enzyme activity and studying temperature effects. Ca[sup 2+] ATPase, assayed by following ATP hydrolysis was thapsigargin- and vanadate-sensitive showed maximum activity under 2 [micro]M Ca[sup 2+], 200 mM KCl and pH 7.2, and had a K[sub M] for ATP of 22 [+-] 7 [micro]M. Temperature effects showed an Arrhenius inversion between [minus]1.8 and 0 C, indicating cold adaptation, an Arrhenius break at 10 C, and a collapse above 20 C. A. colbecki accumulates high amounts of cadmium in the digestive gland; heavy metal effects on sarco-endoplasmic reticulum Ca[sup 2+] ATPases were therefore tested, finding an IC[sub 50] = 0.9 [micro]M for Hg[sup 2+] and 3 [micro]M for Cd[sup 2+]. Finally, SDS-PAGE analysis showed a main band at about 100 kDa, which was identified as sarco-endoplasmic reticulum Ca[sup 2+] ATPase after trypsin digestion, and accounted for 60% total protein.
- OSTI ID:
- 6333833
- Journal Information:
- Polar Biology, Vol. 21:6; ISSN 0722-4060
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANTARCTIC REGIONS
AQUATIC ORGANISMS
ATP-ASE
BIOLOGICAL ADAPTATION
BIOLOGICAL INDICATORS
BIOLOGICAL MARKERS
CADMIUM
INVERTEBRATES
TOXICITY
WATER POLLUTION
ACID ANHYDRASES
ANIMALS
CRYOSPHERE
ELEMENTS
ENZYMES
HYDROLASES
METALS
ORGANIC COMPOUNDS
PHOSPHOHYDROLASES
POLAR REGIONS
POLLUTION
PROTEINS
540320* - Environment
Aquatic- Chemicals Monitoring & Transport- (1990-)
560300 - Chemicals Metabolism & Toxicology