STRUCTURAL CHARACTERIZATION OF HUMAN GLYOXALASE-II AS PROBED BY LIMITED PROTEOLYSIS

Human glyoxalase II is partially proteolyzed by trypsin, under non den aturing conditions, only at the level of the C-terminal region. The pr oteolytic cleavage resulted in an inactivation of the enzyme without l oss of the secondary structure. Sodium dodecyl sulphate polyacrylamide gel-electrophoresis and microsequence analysis showed that the glyoxa lase II is proteolyzed at the level of Arg 184 and Lys 230 and undergo es a third cleavage in a region located at the beginning of the suppos ed C-terminal domain. The proteolysis occurs either in the presence or in the absence of specific inhibitors. Our limited proteolysis experi ments and secondary structure prediction give evidence for the presenc e of two domains characterized by different pattern of secondary struc ture.