The inhibition by melanoidin of trypsin was investigated in a kinetic
approach. Melanoidin was prepared by the Maillard reaction between D-g
lucose and glycine, and BANA was used as a substrate. The inhibition w
as found to follow a non-competitive mode with a K-i of 5.8% and to be
exerted through an electrostatic interaction between melanoidin and t
rypsin. Approximately 20% of the activity of trypsin survived even at
a greatly increased concentration of melanoidin. The inhibiting mechan
ism of melanoidin might be due to an allosteric effect, which was prob
ably different from a proteinaceous inhibitor such as ovoinhibitor dim
inishing trypsin-activity completely. The melanoidin molecule was thou
ght to trap a great number of trypsin molecules, binding them and redu
cing their activity.