Formation of thiazolines within the peptide chain during heating of proteins |
| |
Authors: | Thomas Paulus T Henle Rainer Hae?ner and Henning Klostermeyer |
| |
Affiliation: | (1) Lehrstuhl für Milchwissenschaft, Technische Universit?t München, V?ttinger Strasse 45, D-85350 Freising-Weihenstephan, Germany, DE;(2) Lehrstuhl für Organische Chemie II, Technische Universit?t München, Lichtenbergstrasse 4, D-85748 Garching, Germany, DE |
| |
Abstract: |
L-2-Methyl-4-carboxy-thiazoline was isolated by ion-exchange chromatography and RP-HPLC from heated solutions of N-acetyl-L-cysteine. The structure was established by NMR-spectroscopy. The formation of thiazolines during the heating of cysteine-containing
peptides (glycyl-glycyl-cysteine, glycyl-cysteinyl-glycine, glutathione) was observed by UV and NMR-spectroscopy and measured
by cation-exchange chromatography. The rate of formation was dependent on the pH, the water activity and the temperature.
In comparison with untreated samples, a characteristic increase of absorption at 260 nm in heated proteins (β-lactoglobulin,
ovalbumin) was noticed. Using NMR-spectroscopy two-dimensional: hetero nuclear multiple quantum coherence (HMQC) and total
correlated spectroscopy (TOCSY)] the formation of thiazolines within heated proteins (β-lactoglobulin, egg white albumin and
bovine serum albumin) could be demonstrated unequivocally. The signals of the methine-proton of thiazolines as well as the
coupling constants of the thiazoline protons are very characteristic and not overlaid by signals of protein-bound amino acids.
Received: 26 April 1996 / Revised version: 30 July 1996 |
| |
Keywords: | Thiazolines 2-Methyl-4-carboxy-thiazoline Backbone modification Proteins |
本文献已被 SpringerLink 等数据库收录! |
|