ENZYMATIC SYNTHESIS OF CARBONIC ANHYDRASES BY HUMAN RETICULOCYTES

Human reticulocyte-rich blood incubated 4h at 37° in O2-CO2 (95:5, v/v) with 3H- or 14C-tagged amino acids revealed incorporation of the label into carbonic anhydrase I and II, Hb A, and in one patient, into Hb S. No radioactivity could be detected in normal, nonreticulocyte-rich blood similarly treated. From this, it is concluded that the anucleate human reticulocyte synthesizes carbonic anhydrase I and II by means of a stable messenger RNA in the absence of DNA. During the course of this study, several new methods were developed for the microanalysis of proteins including (1) comparison of labeled protein components after electrophoresis by liquid scintillation counting of consecutive slices of starch gels with autoradiography, (2) isolation of 1-mg quantities of carbonic anhydrase from whole blood hemolysates followed by tryptic digestion and fingerprinting of 0.01 mg samples on thin-layer chromatography support sheets, and (3) autoradiographs of the fingerprints by apposition to AR10 film plates and recording the film reduction by light microscopy and photomicrography. © 1969.