SPINACH CARBONIC-ANHYDRASE - IDENTIFICATION OF 2 IMMUNOLOGICALLY RELATED PROTEIN SPECIES

When submitted to several chromatographic steps, carbonic anhydrase (CA: carbonate dehydratase; EC 4.2. 1.1) of spinach leaves appeared as two closely spaced but distinct bands at M(r) approximate to 28 x 10(3) as indicated by analytical SDS-polyacrylamide gel electrophoresis. Immunochemical analyses demonstrated that both peptides reacted equally with a spinach carbonic anhydrase specific antibody. Two dimensional gel immunoelectrophoretic analysis of CA indicates the presence of charge variants which may arise as a result of chemical modification. Column chromatofocusing also revealed that spinach carbonic anhydrase possesses a pI of approximate to 5.3, which is similar to animal isoforms.