Decreased Coomassie brilliant blue colour yield with glycated proteins

Collagen, myosin and albumin were incubated for 7 days at 20 degrees C with fructose, ribose or glyceraldehyde. For thus-formed glycated proteins, quantities were determined by the Conway microdiffusion technique and by the colorimetric method based on Coomassie brilliant blue G-250 colour yield. It was found that when albumin was glycated with increasing amounts of glyceraldehyde, the colour yield was decreased by 7-33%. In collagen, myosin and albumin incubated with 0.5 mol/l fructose, 0.5 mol/l ribose or 0.1 mol/l glyceraldehyde, protein concentration was not changed, as proved by the Conway microdiffusion technique; the Coomassie brilliant blue G-250 colour yield was up to 50% lower, depending on the protein used, and was decreased much less when proteins were incubated with less sugar.