Open AccessStudies on the Carbohydrate Moiety of Dopamine β-Hydroxylase: Interaction of the Enzyme with Concanavalin A
Author(s) -
Ellen F. Wallace,
Walter Lovenberg
Publication year - 1974
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.71.8.3217
Subject(s) - concanavalin a , chemistry , enzyme , sepharose , biochemistry , lectin , mannose , active site , in vitro
Dopamine β-hydroxylase [EC 1.14.17.1; 3,4-dihydroxyphenylethylamine, ascorbate:oxygen oxidoreductase (β-hydroxylating)], a glycoprotein, was found to interact strongly with the plant lectin, concanavalin A. This interaction did not appear to alter the catalytic properties of the enzyme and did not prevent interaction of the protein with specific antibodies. Dopamine-β-hydroxylase is adsorbed to concanavalin A covalently bound to Sepharose and can be eluted with α-methylmannoside. The enzyme is catalytically active when it is immobilized on a concanavalin A-Sepharose column. Enzymic removal of four of seven mannose residues present in the monomer does not result in the loss of any catalytic activity. It is concluded that the active site is not near the point of carbohydrate attachment on the molecule and that this may be of significance in orienting the enzyme on the vesicular membrane.