obsolete protein-cofactor linkage true OBSOLETE. The covalent attachment of a cofactor to a protein. GO:0018065 1. Making inferences in GO about compounds based on the cofactor role curated by ChEBI creates relationships that are not always true which violates ontological principles for GO; therefore we will cease making these inferences. 2. It is not meaningful to group protein modification processes that are not all chemically related by the fact that they may be used as a cofactor. biological_process