Physicochemical properties and quaternary structure of chick pea leaf carboanhydrase

A homogeneous preparation of carboanhydrase was obtained from Cicer arietinum leaves. The enzyme represents an active protein with isoelectric point 5.55; it sediments in the zone corresponding to 8.95 S, is characterized by a Stokes radius of 51 angstroms, friction ratio 1.31, diffusion coefficient 4.19, and has a molecular weight of similar to 208,000. It was concluded that chick pea leaf carboanhydrase is an octamer, consisting of identical monomers, each of which contains one zinc atom. On the basis of the electron microscopic projections obtained for the molecular of this enzyme, a model was proposed for it.