Binds the chemical odorant 2-isobutyl-3-methoxypyrazine. May form a heterodimer with OBP1B. Expressed in nasal mucosa (at protein level) (PubMed:8529023). Specifically detected in septal and lateral nasal glands (PubMed:9661663). The N-terminus may be blocked. Belongs to the calycin superfamily. Lipocalin family.