Catalyzes the O-methylation, and thereby the inactivation, of catecholamine neurotransmitters and catechol hormones (By similarity). Required for auditory function (By similarity). Component of the cochlear hair cell's mechanotransduction (MET) machinery. Involved in the assembly of the asymmetric tip-link MET complex. Required for transportation of TMC1 and TMC2 proteins into the mechanically sensitive stereocilia of the hair cells. The function in MET is independent of the enzymatic activity (By similarity). a catechol + S-adenosyl-L-methionine = a guaiacol + H(+) + S-adenosyl-L-homocysteine Interacts with LHFPL5, PCDH15, TMC1, TMC2 and TMIE. Interacts directly with TMC1. The interaction of TOMT with TMC1 and TMC2 is required for the transportation of TMC1/2 into the stereocilia of hair cells. Localized to the cell body of the cochlear hair cells, but is not present in the stereocilia. Present but not restricted to the apical cistern, Hensen's body and the subsurface cistern. LRRC51 and TOMT were originally considered as alternative reading frames, LRTOMT1 and LRTOMT2 of the same LRTOMT gene in primates. Belongs to the class I-like SAM-binding methyltransferase superfamily. Cation-dependent O-methyltransferase family.