... Co2þas the cofactor [26]. The class IIBacillus coagulans XI, on the other hand, isomerizesxylose most efficiently when in the presence of Mn2þ,whereas its activity toward fructose is best ... (1),with an r2 of 0.951, is based on the elution data of all four proteinstandards. Linear regression (2), with an r2 of 0.981, is based on the elution data of the 200, 150, and 66 kDa protein standards. ... notsurprising that they are less abundant in proteins fromhyperthermophiles. This observation raises the question of whether a relatively low N þ Q content is a signature of enhanced thermostability...