An O-methyltransferase (OMT) is a type of methyltransferase enzyme transferring a methyl group on a molecule.

Examples are :

• Acetylserotonin O-methyltransferase
• Apigenin 4'-O-methyltransferase
• Caffeate O-methyltransferase
• Caffeoyl-CoA O-methyltransferase
• Catechol O-methyltransferase
• Chlorophenol O-methyltransferase
• Columbamine O-methyltransferase
• Demethylmacrocin O-methyltransferase
• 3'-demethylstaurosporine O-methyltransferase
• Demethylsterigmatocystin 6-O-methyltransferase
• 3-demethylubiquinone-9 3-O-methyltransferase
• 3,7-dimethylquercetin 4'-O-methyltransferase
• Fatty-acid O-methyltransferase
• Glucuronoxylan 4-O-methyltransferase
• 10-hydroxydihydrosanguinarine 10-O-methyltransferase
• 12-hydroxydihydrochelirubine 12-O-methyltransferase
• 6-hydroxymellein O-methyltransferase
• 3'-hydroxy-N-methyl-(S)-coclaurine 4'-O-methyltransferase
• 8-hydroxyquercetin 8-O-methyltransferase
• Iodophenol O-methyltransferase
• Isobutyraldoxime O-methyltransferase
• (iso)eugenol O-methyltransferase
• Isoflavone 4'-O-methyltransferase
• Isoflavone 7-O-methyltransferase
• Isoliquiritigenin 2'-O-methyltransferase
• Isoorientin 3'-O-methyltransferase
• Jasmonate O-methyltransferase
• Protein-L-isoaspartate(D-aspartate) O-methyltransferase
• Kaempferol 4'-O-methyltransferase
• Licodione 2'-O-methyltransferase
• Loganate O-methyltransferase
• Luteolin O-methyltransferase
• Macrocin O-methyltransferase
• Methylquercetagetin 6-O-methyltransferase
• 3-methylquercetin 7-O-methyltransferase
• mRNA (nucleoside-2'-O-)-methyltransferase
• Myricetin O-methyltransferase
• N-benzoyl-4-hydroxyanthranilate 4-O-methyltransferase
• O-demethylpuromycin O-methyltransferase
• 6-O-methylnorlaudanosoline 5'-O-methyltransferase
• Phenol O-methyltransferase
• Polysaccharide O-methyltransferase
• Protein-glutamate O-methyltransferase
• Protein-S-isoprenylcysteine O-methyltransferase
• Quercetin 3-O-methyltransferase
• rRNA (adenosine-2'-O-)-methyltransferase
• (RS)-norcoclaurine 6-O-methyltransferase
• (S)-scoulerine 9-O-methyltransferase
• Sterigmatocystin 8-O-methyltransferase
• Tabersonine 16-O-methyltransferase
• Tetrahydrocolumbamine 2-O-methyltransferase
• Tocopherol O-methyltransferase
• tRNA guanosine-2'-O-methyltransferase
• Vitexin 2"-O-rhamnoside 7-O-methyltransferase
• Xanthotoxol O-methyltransferase