Sequences were identified for 275 putative orphan enzymes, most frequently by fixing database errors.

Sequences were found for 275 putative orphan enzymes (25% of the total) by searching through the literature, sequence databases, and patents. Approximately half of the orphans for which sequences could be found were “annotation updates,” in which the sequence for the enzyme in major databases was annotated with no activity, with a less specific activity, with an incorrect activity that was in the same general class as the correct one, or with another correct activity that the enzyme also carries out. The remaining orphans fell into the “data inconsistency” category. Orphan enzymes in this category were in some way annotated to sequence data, but a lack of an EC number or a nomenclature mismatch meant that searching these databases for the activity did not yield any sequence data.