Probing structure-activity relationship in diamine oxidase--reactivities of lysine and arginine residues.
Lysine and arginine residues of pig kidney diamine oxidase (DAO) were modified with 2,4,6-trinitrobenzenesulphonic acid (TNBS), 2,3-butanedione and phenylglyoxal, respectively, using different concentrations and time periods. Lysine residues are classified into 3 categories: completely exposed, highly reactive; sluggish, partly buried; and unreactive, completely buried. About 21 lysine residues whose modification did not lead to any significant conformational change as well as loss of catalytic activity are believed to be less important for the structural stability of the enzyme. On the other hand, the remaining 19 lysine residues are more important in maintaining the native structure of the enzyme as evidenced by the change in hydrodynamic parameters and loss of catalytic activity upon their modification. Arginine residues when probed with butanedione or phenylglyoxal treatment resulted in the significant loss of catalytic activity without any change in conformation implicating their involvement in the catalytic function of the enzyme. Significant change in conformation was noted when 10 arginine residues were modified, which suggests the structural role of these residues.
Shah
M A
MA
Department of Biochemistry, Aligarh Muslim University, India.
Tayyab
S
S
Ali
R
R
D006631:Amine Oxidase (Copper-Containing) / Q000737:chemistry* / Q000378:metabolism*; D001120:Arginine / Q000737:chemistry*; D003931:Diacetyl / Q000737:chemistry; D008239:Lysine / Q000737:chemistry*; D010658:Phenylglyoxal / Q000737:chemistry; D011487:Protein Conformation; D013329:Structure-Activity Relationship; D013816:Thermodynamics; D013997:Time Factors; D014302:Trinitrobenzenesulfonic Acid / Q000737:chemistry
D014302:Trinitrobenzenesulfonic Acid; D001120:Arginine; D006631:Amine Oxidase (Copper-Containing); D003931:Diacetyl; D008239:Lysine; D010658:Phenylglyoxal