PURIFICATION AND CHARACTERIZATION OF BILIVERDIN-ASSOCIATED CYANOPROTEIN FROM EGGS AND HEMOLYMPH OF THE BEAN BUG, RIPTORTUS-CLAVATUS (HETEROPTERA, ALYDIDAE)

Biliverdin binding protein, cyanoprotein (CP), was purified from egg extracts of the bean bug, Riptortus clavatus. The preparation was shown to be homogeneous by DEAE-chromatography and polyacrylamide gel electrophoresis (PAGE). The native molecular weight (MW) of egg CP (CPegg) was estimated to be 320,000 by PAGE and 335,000 by gel filtration. The apoprotein consisted of identical subunits with MW of 76,000. CPegg had a high content of aromatic amino acids (17% mol ratio) with absorbance peaks at 370 and 620 nm which are characteristic of biliverdins. Native CPegg was associated non-covalently with 16 molecules of biliverdin. CPegg contained about 13.0% neutral sugar (mainly mannose) associated covalently with the apoprotein, no lipid was detected. In the hemolymph of the bugs, four CP bands (CP1, 2, 3 and 4) were detected by native PAGE. These bands were immunologically related and showed properties similar to CPegg in biochemical analysis. Only CP1 was identical to CPegg. CPs specific to the hemolymph, CP2, 3 and 4, were different from CPegg in mobility by PAGE, pI and peptide mapping profiles. © 1990.