Interactions of isothiocyanates with egg white proteins

✍ Scribed by Kroll, J. ;Rawel, H. ;Kröck, R. ;Proll, J. ;Schnaak, W.

• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 419 KB
• Volume: 38
• Category: Article
• ISSN: 0027-769X
• DOI: 10.1002/food.19940380110

✦ Synopsis

Abstract

Glucosinolates and their very highly reactive breakdown products (mainly isothiocyanates = ITC) belong to one of the most important natural toxicants. This paper deals with the interactions of allyl‐, butyl‐, phenyl‐ and benzyl ITC with egg white proteins resulting in the formation of ITC‐protein‐conjugates. The ITC's react with amino groups by forming thiourea derivatives. Such reactions are well described by changes in the amounts of free amino groups and available lysine. Further reaction sites are sulphhydryl side chains of proteins leading to dithiocarbamate esters. The investigations further show that such reactions are accompanied with a decrease in the solubility of the prepared conjugates. Simultaneously a shift of the isoelectric range to a lower value of pH can also be observed. Changes in electrophoretic patterns and mobility can also be seen due to the strong electrophilic attack of ITC to proteins. Comparison of the 4 investigated preparations shows that benzyl‐ITC is the most reactive partner for egg white proteins.