Marc Melchior Deconinck

Binding capacities of various analogues of S-adenosyl-L-homocysteine to protein methyltransferase II from human erythrocytes

A series of analogues of S-adenosyl-L-homocysteine, modified mainly in the amino acid portion of the molecule, have been synthesized. All were found to be competitive inhibitors of protein methyltransferase II from human erythrocytes. S-adenosyl-L-homocysteine remains however by far the most effective inhibitor of the methylase.

Isolation and characterization of chicken (Gallus gallus) and penguin (Aptenodytes forsteri) myoglobins

Summary Methods describing isolation, purification and characterization of two avian myoglobins are reported. Chicken myoglobin was extracted at 55 to 90 p. cent ammonium sulfate saturation, while penguin myoglobin was isolated by low temperature fractionation using ethanol in the presence of metallic ions. Both were purified by gel filtration and chromatography on CM Sephadex and their homogeneity was tested by zone electrophoresis with different gels. The amino acid compositions have been determined. Chicken hemoprotein appears very similar to previously studied myoglobin, but penguin hemoprotein differs significantly, essentially by a higher amount of methionine. Both proteins have glycine as the aminoterminal residue. The molar extinction coefficients and the reduced mean residue optical rotation were found to be identical.

Reoxidation of reduced hen egg white lysozyme fragment 1-123.

The reactivation of reduced lysozyme, whose 6 COOH-terminal amino acid including cysteine 127 were cut off, was studied. The results show that the disulfide bridge I–VIII as well as the COOH-terminal hexapeptide do not play a decisive role in the acquisition of the native 3-dimensional structure of the enzyme.

Carboxypeptidase Y from Saccharomyces cerevisiae: Circular dichroism and fluorescence studies

Carboxypeptidase Y was isolated fromSaccharomyces cerevisiae and its molecular structure investigated. The enzyme in the native state possesses 40% of its amino acid residues in a β-conformation. Its tryptophan residues seem to be largely buried in an apolar and unsymmetrical environment.