THE RELATION OF INFLAMMATION TO THE MOLECULAR STRUCTURE OF CARBON COMPOUNDS SOLUBLE IN THE FLUIDS OF THE BODY

The peritoneal, like the pleural cavity, gives opportunity to measure with adequate accuracy the activity of inflammatory reactions defined by movement of fluid within the cavity, by migration of leucocytes into it, and by exudation of proteins from the plasma. The activity of inflammatory reactions caused by saccharides or by alcohols that were tested varied in accord with their molecular weight, the osmotic pressure maintained by solutions of corresponding concentration, their boiling point, or by other colligative properties. Blood serum or globulin in the concentration with which it occurs in blood serum injected into the peritoneal cavity caused changes which differed little from those caused by physiological salt solution. Protein with molecular weight as low as that of cytochrome C (12,000) or ovalbumin (45,000) when in dilute solution (1 per cent) were rapidly absorbed, whereas trypsin and chymotrypsin under the same conditions caused very active inflammatory reactions because they set free amino acids and perhaps polypeptides with amino acids in short chains. The activity of inflammatory reactions caused by carbon compounds soluble in body fluids varied in accord with their colligative properties.

THE PHOTOASSIMILATION OF SUCCINATE TO HEXOSE BY RHODOSPIRILLUM RUBRUM

1. A pathway for the synthesis of hexose from succinate by Rhodospirillum rubrum is proposed. 2. With 2,3-(14)C(2)-labelled succinate and fumarate as substrates in experiments with chromatophores and a soluble enzyme fraction of R. rubrum it was found that the products of succinate metabolism by the extracts were the same as in whole cells. It was also found that the light-dependent oxidation of succinate was catalysed by the chromatophores, but that all the other enzymes involved were in the soluble fraction. 3. By using specific assays the presence of all the enzymes required for the proposed pathway was demonstrated in the extracts and their specific activities were measured. 4. The overall rate of succinate assimilation was measured manometrically. The activities of the enzymes assayed were sufficient to account for the overall rate of assimilation. It is concluded that the proposed pathway represents the major mechanism for synthesis of hexose from succinate in R. rubrum. 5. The formation of alanine and aspartate was observed in experiments with isotopically labelled substrates, and possible synthetic pathways for these compounds are discussed.

THE CARBOHYDRATE-POLYPEPTIDE LINKAGES, THE AMINO ACID SEQUENCES OF THE PEPTIDES ADJACENT TO SOME OF THESE BONDS, AND THE COMPOSITION AND SIZE OF THE CARBOHYDRATE UNITS OF ALPHA-1-ACID GLYCOPROTEIN

1. The glycopeptides derived from a proteolytic digest of sialic acid-free alpha(1)-acid glycoprotein were separated on a DEAE-cellulose column into five main fractions. 2. The average molecular weight of these glycopeptides was 2400, except for one fraction whose molecular weight was 3100. The average molecular weight of the sialic acid-free carbohydrate units was found to be 2200. From these data and the carbohydrate content of the native protein and the assumed molecular weight of 44000, it was concluded that alpha(1)-acid glycoprotein probably possesses five carbohydrate units. The sialic acid-containing carbohydrate units of this glycoprotein have an average molecular weight of 3000, except for one unit the molecular weight of which is significantly higher. 3. The N-, non-N- and C-terminal amino acids of the main glycopeptides were determined. Aspartic acid and threonine occur in most peptides. Alanine, glycine, proline, serine and lysine were present in varying amounts. Traces of other amino acids were also found. 4. The amino acid sequence of three main glycopeptides was established and indicated that these glycopeptides are located at different positions of the polypeptide chain of the glycoprotein. These sequences are: Asp(NH(2))-Pro-Lys; Thr-Asp(NH(2))-Ala; Asp(NH(2))-Gly-Thr. 5. From the results of a series of chemical reactions (periodate oxidation, hydrazinolysis, dinitrophenylation, mild acid hydrolysis) it was shown that the hydroxyl group of the N-terminal threonine and the in-amino group of lysine are free and that the beta-carboxyl group of aspartic acid is present as amide. It was concluded that this amide group is involved in the carbohydrate-polypeptide linkages of at least four carbohydrate units of alpha(1)-acid glycoprotein. 6. The carbohydrate composition of the sialic acid-free glycopeptides was determined in terms of moles of neutral hexoses, glucosamine and fucose/mole. 7. Fucose, at least to the larger part, is not linked to sialic acid, and its (glycosidic) linkage is significantly more stable toward acid hydrolysis than the bond of the sialyl residues. 8. Heterogeneity of the carbohydrate units of alpha(1)-acid glycoprotein was found with regard to size and to content of fucose and sialic acid.