FIG 7.

Enzyme activities in C. difficile that reflect metabolic pathways active under different growth conditions. Enzymes involved in a number of key pathways were assayed in anaerobic cell extracts prepared from large-scale growths of C. difficile in BHIS and defined media indicated at the top. Gly/Ala 2.2 and Gly/Ala 0.5 indicate Gly/Ala growths with 2.2 and 0.5 mM glucose remaining at the time of harvest. The substrates and products in bold font were measured directly in the assays described in Materials and Methods. Enzyme specific activities are given in units per milligram extract protein. MV, methyl viologen; BV, benzyl viologen; H₄F, tetrahydrofolate.