beta-Cyclodextrin inhibits the sweet taste suppressing activity of gurmarin by the formation of an inclusion complex with aromatic residues in gurmarin
T. Imoto et al., beta-Cyclodextrin inhibits the sweet taste suppressing activity of gurmarin by the formation of an inclusion complex with aromatic residues in gurmarin, CAN J PHYSL, 79(10), 2001, pp. 836-840
Our recent study in mice revealed that the inhibitory activity of gurmarin
on the sweet taste responses was reduced significantly by the presence of b
eta -cyclodextrin (beta -CD). To investigate the mechanism involved in the
action of beta -CD, physicochemical experiments were performed on the inter
action of CDs with gurmarin examining the effect of CDs on the UV absorptio
n spectrum of gurmarin and on the elution behavior in gel filtration (or ex
clusion) chromatography. Among the three kinds of cyclodextrins tested, bet
a -CD induced significant changes in the UV absorption spectrum of gurmarin
that were characteristic of those found in the inclusion complex formation
of tyrosine and tryptophan with beta -CD. The abnormal retention behavior
of gurmarin in gel filtration resulting from hydrophobic interaction with t
he gel matrix reverted to normal in the presence of beta -CD in the elution
buffer. These results suggest that the unique domain of gurmarin, in which
five aromatic amino acid residues are all directed outwardly and form a hy
drophobic cluster, is a possible site of interaction with the gurmarin-sens
itive sweet taste receptor molecules in rodents.