Major facilitator-type transporter, part of the hnx cluster involved in the purine degradation (PubMed:29212709). The nicotinate hydroxylase hnxS accepts nicotinate as a substrate and catalyzes the first step of nicotinate catabolism (PubMed:29212709). The major facilitator-type transporters hxnP and hxnZ are probably involved in the uptake of nicotinate-derived metabolites, and the oxidoreductases hxnT and hxnY in the further metabolism of 6-OH nicotinic acid (PubMed:29212709). Expression is induced by nicotinate and 6-OH nicotinate, subject to nitrogen metabolite repression mediated by the GATA factor areA, and strictly regulated by the cluster-specific transcription regulator hnxR (PubMed:29212709). Belongs to the major facilitator superfamily.