PIXE analysis of Zn enzymes

Zinc is a necessary component in the action and structural stability of man y enzymes, Some of them are well characterized, but in others, Zn stoichiom etry and its association is not known, PIXE has been proven to be a suitabl e technique for analyzing metallic proteins embedded in electrophoresis gel s. In this study, PIXE has been used to investigate the Zn content of enzym es that are known to carry Zn atoms. These include the carbonic anhydrase, an enzyme well characterized by other methods and the cytoplasmic pyrophosp hatase of Rhodospirillum rubrum that is known to require Zn to be stable bu t not how many metal inns are involved or how they are bound to the enzyme, Native proteins have been purified by polyacrylamide gel electrophoresis a nd direct identification and quantification of Zn in the gel bands was perf ormed with an external proton beam of 3.7 MeV energy. (C) 1999 Elsevier Sci ence B.V. All rights reserved.