["Preparative" chromatographic fractionation of human carbonic anhydrase isoenzymes. Specific studies on their identification].

The AA. describe a technique for chromatographic fractionation of the isoenzymes of carbonic anhydrase. They utilized a hydroxylapatite column, soaking the isoenzymes suspension at its top. As eluting solutions they utilized a series of phosphate buffers, pH 6,8, at increasing ionic strength. The elution, allowed the separation of three fractions which the AA. identified by spectrophotometric, electrophoretic and immunologic analysis and by atomic absorption spectrophotometry. -- Electrophoretic analysis showed that the "first fraction" eluted from the chromatographic column corresponding to the first peak, contained 8,5% of total protein, the "second chromatographic fraction", corresponding to the second electrophoretic peak contained 82,5%, whereas the "third" contained 9%. -- Nitrogen contents in the three eluted fractions showed the following values: 6,6% in the first fraction, 85,5% in the second, 8% in the third. These values are very near the ones obtained from ferogram. -- Spectrophotometric analysis revealed similar structure for the three fraction, in the range 230-300 nm of spectrum and a second peak at 400 nm for the third eluted fraction. -- The atomic spectrophotometric absorption revealed the presence of zinc in the three fractions, the amount of the element resulted almost constantly related to the nitrogen concentration in each of them.