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

Nuno Borges, Ana Ramos, Neil D.H. Raven, Richard J. Sharp, Helena Santos

Research output: Contribution to journalArticle

134 Citations (Scopus)

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.

Original languageEnglish
Pages (from-to)209-216
Number of pages8
JournalExtremophiles
Volume6
Issue number3
DOIs
Publication statusPublished - 1 Dec 2002

Keywords

  • Compatible solutes
  • Lactate dehydrogenase
  • Mannosylglycerate
  • Thermal stabilization

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