5. Über die Oxydation des Lysozyms mit Perjodat

Abstract

Lysozyme was oxidized with sodium meta-periodate, and the following results were obtained from investigations of the process of oxidation and the changes of lytic activity and absorption spec 1) K.

Reversible reductive alkylation of amino groups in proteins

“…Reversible Modification of Lysozyme. Lysozyme was chosen as the protein for the first experiments in modification with glycolaldehyde, followed by its reversal with periodate, mainly because its amino groups are not intimately involved in the catalytic process, and there has been a report of its inactivation by periodate (Maekawa & Kushibe, 1955). The inactivation was related to the destruction of a tryptophan residue in the enzyme, and its extent was linearly related to a decrease in the absorbance at 280 nm.…”

The Periodate Oxidation of Amino Acids With Reference to Studies on Glycoproteins

“…The oxidation of amino acid residues when they are combined as in peptides and proteins has been less well studied. Oxidation with periodate has been shown to cause loss ofbiological activity in many proteins, including ribonuclease, immune globulins and virus (Goebel, Olitsky & Saenz, 1946), lysozyme (Maekawa & Kushibe, 1955), lactate dehydrogenase (Nygaard, 1956), glucosidase and phosphatase (Bossard, 1948 When ovalbumin, the egg-white glycoprotein, was oxidized by periodate for a short period without causing denaturation, only cysteine and tryptophan residues were appreciably destroyed, and tyrosine, histidine and cystine were largely unaffected (Maekawa & Kushibe, 1954). When ovalbumin was oxidized more extensively at pH 5-5 until it was denatured (Desnuelle, Antonin & Casal, 1947), it consumed approx.…”