Salsolinol　(1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline),　a　derivate　of　dopamine,　is　suspected　to　be　the　most　probable　neurotoxin　in　the　degeneration　of　dopaminergic　neurons.　Numerous　hypotheses　regarding　its　pathophysiological　roles　have　been　raised,　especially　related　to　Parkinson＇s　disease　and　alcohol　addiction.　In　the　mammalian　brain,　salsolinol　may　be　enzymatically　synthesized　by　salsolinol　synthase　from　dopamine　and　acetaldehyde.　However,　the　direct　evidence　of　its　biosynthesis　was　still　missing.　In　this　study,　we　purified　salsolinol　synthase　from　rat　brain　by　a　systematical　procedure　involving　acid　precipitation,　ultra　filtration,　and　hydrophilic　interaction　chromatography.　The　molecular　weight　of　salsolinol　synthase　determined　by　MALDI-TOF　MS　is　8622.29　Da,　comprising　77　amino　acids　(MQIFVKTLTG　KTITLEVEPS　DTIKNVKAKI　QDKEGIPPDQQRLIFAGKQL　EDGRTLSDYN　IQKKSTLHLV　LRLRVDY).　Homology　analysis　showed　that　the　enzyme　is　a　ubiquitin-like　protein,　with　a　difference　of　four　amino　acids,　which　suggests　it　is　a　novel　protein.　After　it　was　overexpressed　in　eukaryotic　cells,　the　production　of　salsolinol　was　significantly　increased　as　compared　with　control,　confirming　the　catalytic　function　of　this　enzyme.　To　our　knowledge,　it　is　the　first　systematic　purification　and　sequencing　of　salsolinol　synthase.　Together,　this　work　reveals　a　formerly　anonymous　protein　and　urges　further　exploration　of　its　possible　prognostic　value　and　implications　in　Parkinson＇s　disease　and　other　related　disorders.