Glycyl radical enzyme activase <p> This subset of the radical-SAM domain includes a number of probable activating proteins acting on different enzymes all requiring an amino-acid-centred radical. The closest relatives to this family are the pyruvate-formate lyase activating enzyme (PflA, <db_xref db="EC" dbkey="1.97.1.4"/>, <db_xref db="INTERPRO" dbkey="IPR012838"/>) and the anaerobic ribonucleotide reductase activating enzyme (<db_xref db="INTERPRO" dbkey="IPR012837"/>). Included within this subfamily are activators of hydroxyphenyl acetate decarboxylase (HdpA, [<cite idref="PUB00016705"/>]), benzylsuccinate synthase (BssD, [<cite idref="PUB00016708"/>]), gycerol dehydratase (DhaB2, [<cite idref="PUB00016707"/>]) as well as enzymes annotated in <taxon tax_id="562">Escherichia coli</taxon> as activators of different isozymes of pyruvate-formate lyase (PFLC and PFLE) however, these appear to lack characterisation and may activate enzymes with distinctive functions. Most of the sequence-level variability between these forms is concentrated within an N-terminal domain, which follows a conserved group of three cysteines and contains a variable pattern of 0 to 8 additional cysteines.</p>