title: Characterization of recombinant human aromatic L-amino acid decarboxylase expressed in COS cells.
abstract: The expression vector containing the full-length cDNA of human aromatic L-amino acid decarboxylase (EC 4.1.1.28) was transfected in COS cells by a modified calcium phosphate coprecipitation method. The cells transfected with plasmids that had a true direction of the cDNA gave a major immunoreactive band at 50 kDa. This expressed enzyme catalyzed the decarboxylation of L-3,4-dihydroxyphenylalanine (L-DOPA), L-5-hydroxytryptophan (L-5-HTP) and L-threo-3,4-dihydroxyphenylserine. The optimal pH of the enzyme activity with L-DOPA as a substrate was 6.5, whereas the enzyme had a broad pH optimum when L-5-HTP was used as a substrate. Addition of pyridoxal phosphate to the incubation mixture greatly enhanced the activity for both L-DOPA and L-5-HTP.
authors.affiliation: Department of Biochemistry, Nagoya University School of Medicine, Japan.
authors.forename: C
authors.initials: C
authors.lastname: Sumi
authors.forename: H
authors.initials: H
authors.lastname: Ichinose
authors.forename: T
authors.initials: T
authors.lastname: Nagatsu
mesh_terms: D006916:5-Hydroxytryptophan / Q000378:metabolism; D001142:Aromatic-L-Amino-Acid Decarboxylases / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D004247:DNA / Q000235:genetics; D004295:Dihydroxyphenylalanine / Q000378:metabolism; D015103:Droxidopa / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D010957:Plasmids; D011732:Pyridoxal Phosphate / Q000494:pharmacology; D011994:Recombinant Proteins / Q000378:metabolism*; D013379:Substrate Specificity; D014162:Transfection
chemical_list: D011994:Recombinant Proteins; D011732:Pyridoxal Phosphate; D004295:Dihydroxyphenylalanine; D004247:DNA; D006916:5-Hydroxytryptophan; D001142:Aromatic-L-Amino-Acid Decarboxylases; D015103:Droxidopa