Isolation and characterization of rabbit H of the alternative complement pathway

Rabbit factor H, a control protein of the alternative complement pathway, was isolated from rabbit serum by polyethylene glycol precipitation, DEAE-Sephacel chromatography, and gel chromatography on Sephadex G200. The protein migrated as a single-chain polypeptide with a molecular weight of 160,000 on sodium dodecyl sulfate-gel electrophoresis with Laemmli's buffer system, but hardly migrated into the gel with Fairbanks' buffer system. Physical and chemical properties of rabbit H were similar to those of human H, except that fragments produced by limited tryptic digestion from rabbit H had different molecular sizes from those produced from human H. Significant species-specificity was observed in the functional activity of factor H; activation of the alternative complement pathway was inhibited more efficiently with homologous H than with heterologous H. In contrast, factor H inhibited the hemolysis of homologous erythrocytes less than that of heterologous erythrocytes.     

Neutral glycosphingolipids of ova of the fresh-water bivalve, Hyriopsis schlegelii

The neutral glycosphingolipids of ova of the fresh-water bivalve, Hyriopsis schlegelii were characterized. The most abundant glycolipid was ceramide monosaccharide, followed by ceramide trisaccharide, ceramide tetrasaccharide, and ceramide disaccharide. More complex neutral glycolipids accounted for almost one-third of the total. The total amount of these glycolipids was 0.59 mg/g of dry weight of the ova preparation, a yield which was one-seventh of that of spermatozoa neutral glycolipids. Structural analyses were performed by enzymatic hydrolysis of the glycolipids with exoglycosidases, permethylation experiments, and also immuno-chemical assays. The proposed structures are as follows: ceramide monosaccharides, Gal-Cer and Glc-Cer; ceramide disacharides, Gal(beta 1-4)Gal-Cer, Gal(beta 1-4)Glc-Cer, and Man(beta 1-4)Glc-Cer; ceramide trisaccharide, Man(alpha 1-3)Man(beta 1-4)Glc-Cer; ceramide tetrasaccharides, Man(alpha 1-3)[Xyl(beta 1-2)]Man(beta 1-4)Glc-Cer, GlcNAc(beta 1-2)Man(alpha 1-3)Man(beta 1-4)Glc-Cer, Man(alpha 1-3)[Gal(beta 1-2)]Man(beta 1-4)Glc-Cer, and Man(alpha 1-2?)Man(alpha 1-3)Man(beta 1-4)Glc-Cer. The latter two ceramide tetrasaccharides were new types of glycosphingolipids. The spectrum of ova glycolipids appeared to be more complicated than that of the spermatozoa glycolipids. The ova glycolipids characterized here, with the exception of ceramide tetrasaccharides, contained considerable amounts of 2-hydroxy fatty acids, which were not observed in the spermatozoa glycolipids. The major sphingosine base was C18-sphingenine in all the ova glycolipids as well as in the spermatozoa glycolipids. However, the content of anteiso type of sphingosine base was 2- to 3-fold higher in the ova than in the spermatozoa.     

Oxidation of nitroxide radicals by the reaction of hemoglobin with hydrogen peroxide

The ESR signal of 4-hydroxy-1-oxyl-2,2,6,6-tetramethylpiperidine in hemoglobin solution decreased drastically by the addition of hydrogen peroxide. The results of ion-exchange chromatography and sodium tetraphenylborate on the reaction solution showed an oxidation of the nitroxide radical to cation form. On the basis of the comparison of thin layer-chromatogram with the reaction products of the nitroxide radicals with HCl or Br2, the formation of 4-hydroxy-1-oxo-2,2,6,6- tetramethylpiperidinium cation was demonstrated. This result was supported by the 13C NMR measurement.     

Characterization and immunochemistry of pyruvate dehydrogenase complex of Ascaris muscle

Pyruvate dehydrogenase complex and lipoamide dehydrogenase were purified from muscle of Ascaris lumbricoides var. suum which contains relatively a large amount of the complex. Molecular weights of three constituent enzymes of Ascaris pyruvate dehydrogenase complex were as follows; alpha- and beta-subunits of pyruvate dehydrogenase were 42,000 and 37,000, respectively, lipoate acetyltransferase was 76,000 and lipoamide dehydrogenase was 56,000. Furthermore, two unknown polypeptides having molecular weight of 46,000 and 41,000 were detected. Anti-Ascaris lipoamide dehydrogenase antibody precipitated three constituent enzymes and two unknown polypeptides, suggesting that lipoamide dehydrogenase not only binds tightly to complex, but also two unknown polypeptides bind tightly to complex.     

Raman diagnosis of nucleic acid structure: sugar-puckering and glycosidic conformation in the guanosine moiety.

Observations of Raman spectra of various nucleic acids indicate that the guanine ring breathing frequency is sensitive to the internal rotation angle around the glycosidic bond and to the conformation of the five-membered ring of the ribose residue that is directly connected with the guanine residue in question. It is found that 682 cm-1 for C2'-endo-anti, at 665 cm-1 for C3'-endo-anti, and at 625 cm-1 for C3'-endo-syn. A DNA octamer d(GpGpApApTpTpCpC) shows, in its aqueous solution, a broad Raman band at 680 cm-1 with a tail at 670 cm-1. This fact suggests that the guanosine residues in this oligomer take primarily C2'-endo-anti conformation but an appreciable amount of fluctuation of the ribose ring structure towards C3'-endo is involved.     

Small-angle X-ray scattering of pig thyroglobulin in solution (Short Communication)

Small-angle X-ray scattering measurements on native pig thyroglobulin in phosphate buffer, pH6.9, yield a radius of gyration of 6.4nm (64Å), a particle volume of approx. 1.5×10³nm³ (1.5×10⁶ų), an axial ratio of 2.2:1 (assuming an ellipsoidal shape), and a solvation of 0.63g of solvent/g of protein.