HNMT GI:66932965 histamine N-methyltransferase isoform 3 1 massmrslfs dhgkyvesfr rflnhstehq cmqefmdkkl pgiigrigdt 50 51 kseikilsig ggadclirgs srvlkrnscf ilcstrqkdk pgmrihders 100 101 selpfgaarl esksafpsfl vsfilf