Triose phosphate isomerases (TIMs) are considered to be 'kinetically perfect' enzymes, limited in their activity only by the rates of diffusion of substrate and product molecules. Most studies conducted thus far have been on mesophile-derived TIMs. Here, we report studies of two extremophile-derived TIMs produced in Escherichia coli: (i) TonTIM, sourced from the genome of the thermophile archaeon, Thermococcus onnurineus, and (ii) PfuTIM, sourced from the genome of,the hyperthermophile archaeon, Pyro coccus furiosus (PfuTIM). Although these enzymes are presumed to have evolved to function optimally at temperatures close to the boiling point of water, we find that TonTIM and PfuTIM display second-order rate-constants of activity (k(cat)/K-m values) comparable to mesophile-derived TIMs, at 25 degrees C. At 90 degrees C, TonTIM and PfuTIM reach maximum velocities of reaction of similar to 10(6)-10(7) mu mol/s/mg, and display k(cat)/K-m values in the range of similar to 10(10)-10(11) M-1 s(-1), which are three orders of magnitude higher than those reported for mesophile TIMs. Further, the two enzymes display no signs of having undergone any structural unfolding at 90 degrees C. Such enzymes could thus probably be called 'super-perfect' enzymes. (C) 2015 Elsevier Inc. All rights reserved.