Extremophiles

, Volume 6, Issue 3, pp 209–216

Comparative study of the thermostabilizing properties of mannosylglycerate and other compatible solutes on model enzymes

  • Nuno Borges
  • Ana Ramos
  • Neil D. Raven
  • Richard J. Sharp
  • Helena Santos
Original paper

Abstract.

The protection of mannosylglycerate, at 0.5 M concentration, against heat inactivation of the model enzyme lactate dehydrogenase (LDH) was compared to that exerted by other compatible solutes, namely, trehalose, ectoine, hydroxyectoine, di-myo-inositol phosphate, diglycerol phosphate, and mannosylglyceramide. Mannosylglycerate and hydroxyectoine were the best stabilizers of the enzyme and showed comparable protective effects. Diglycerol phosphate, trehalose, and mannosylglyceramide protected the enzyme to a lower extent. Ectoine conferred no protection, and di-myo-inositol phosphate had a strong destabilizing effect. The superior ability of mannosylglycerate to prevent LDH inactivation was accompanied by a higher efficiency in preventing LDH aggregation induced by heat stress. Moreover, mannosylglycerate induced an increase of 4.5°C in the melting temperature of LDH, whereas the same molar concentration of trehalose caused an increase of only 2.2°C. The effectiveness of mannosylglycerate in protecting LDH was also compared to that of other chemically related compounds: mannose, methyl-mannoside, potassium glycerate, glucosylglycerol, glycerol, and glucose. Mannosylglycerate conferred the highest protection, but glucosylglycerol and potassium glycerate were very efficient; glucose exerted a low degree of protection, glycerol and methyl-mannoside had no significant effect, and mannose caused destabilization. Mannosylglycerate was also a good thermoprotectant of glucose oxidase from Aspergillus niger, an enzyme with a net charge opposite to that of LDH under the working conditions. Given the superior performance of mannosylglycerate as a thermoprotectant of enzyme activity in vitro, it is conceivable that it also fulfills a protein thermoprotective function in vivo.

Mannosylglycerate Compatible solutes Thermal stabilization Lactate dehydrogenase 

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Copyright information

© Springer-Verlag 2002

Authors and Affiliations

  • Nuno Borges
    • 1
  • Ana Ramos
    • 1
  • Neil D. Raven
    • 2
  • Richard J. Sharp
    • 2
  • Helena Santos
    • 1
  1. 1.Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Rua da Quinta Grande 6, Apt. 127, 2780-156 Oeiras, Portugal
  2. 2.Centre for Applied Microbiology and Research, Porton Down, Salisbury, UK

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