Therefore, SaIDH was more thermostable than monomeric IDHs from C. maris and C. psychrerythraea which exhibited maximal activity at 20 and 25℃ (respectively) and were inactivated rapidly at 30℃ [21, 24], but was less thermostable than CgIDH which retains 50% of initial activity at 46℃ for 20 min [17].