Glycosylation sites of hemocyanins of Helix pomatia and Sepia officinalis

Glycopeptides were isolated from functional units of two molluscan hemocyanins (Hcs). They were analyzed and localized in the sequences. A comparison with potential N-glycosylation sites of two other molluscan Hcs was made. An immunological cross-reactivity was observed between the beta-Hc and the alpha-macroglobulin of Helix pomotia. ELISA experiments with glycopeptide fractions indicated a competition.     

Gel Chromatographic Fractionation and Partial Physicochemical Characterization of Gelatins

Summary Gel chromatography on Sephacryl S-400 HR was used to fractionate a type A and a type B gelatin on a semi-preparative scale. Fractionation was performed at 40 °C in 50 mM ammonium acetate, 0.02% (w/v) sodium azide. Five fractions, enriched in microgels, -chains, -chains, -chains and subfragments, were isolated. Their molar mass distribution was controlled by FPLC on Superose 6 and SDS-PAGE. No significant differences in amino-acid composition and hexose content were observed between the original gelatins and their fractions. The specific absorption coefficient at 230 nm was found to be the same for both type A and type B gelatin and the chromatographic fractions (2.0 L·g^–1·cm^–1).Presented at: International Symposium on Separation and Characterization of Natural and Synthetic Macromolecules, Amsterdam, The Netherlands, February 5–7, 2003     

Preparation of d,l-Phenylalanine by Amidocarbonylation of Benzyl Chloride

The preparation of d,l-phenylalanine via amidocarbonylation of benzyl chloride with acetamide and CO/H(2) is described. The rate of the reaction is dependent upon the CO pressure below 250 bar, but independent of the hydrogen pressure. A reaction temperature of 100 degrees C gives optimum yields. A relatively large amount of the catalyst, Co(2)(CO)(8), is needed for complete conversion because of inhibition caused by hydrogen chloride which is formed during the reaction. Addition of NaHCO(3) removes HCl as insoluble NaCl, resulting in improved conversion and selectivity of the reaction. It also allows the use of a stoichiometric amount of acetamide, whereas a 2- to 3-fold excess of acetamide is needed for complete conversion of benzyl chloride without NaHCO(3). Amidocarbonylation of benzyl alcohol gave d,l-phenylalanine in only 8% yield.