This family contains Antigen85 responsible for high affinity of mycobacteria for fibronectin. Proteins of the antigen 85 possess a mycolyltransferase activity required for the biogenesis of trehalose dimycolate (cord factor), a dominant structure necessary for maintaining cell wall integrity. Mycobacterium tuberculosis MPT51 (FbpC1) is a non-catalytic alpha/beta hydrolases member of this family. This family corresponds to a subset of the the Carbohydrate Esterase family CE1 in CAZy - Carbohydrate-Active enZYmes database (CE_1)