L-glutamate binds. The closed conformation facilitates interactions between the upper and lower lobe and allows binding of IMP. The IMP stabilizes the closed conformation of the VFTD and effectively locks this domain. The negatively charged phosphate group on IMP coordinates the positively charged amino acid residues in the lobe of the VFTD

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Umami and taste enhancement - Umami perception: Synergy of L-Glu with IMP

6 important questions on Umami and taste enhancement - Umami perception: Synergy of L-Glu with IMP

Which amino acid induces the umami perception?

L-glutamate (L-Glu)

Which molecule can enhance the umami perception?

Inositol monophosphate (IMP)

What happens when L-glutamate binds in the hinge region of VFTD?

It forms hydrogen bonding with a number of conserved amino acids.
The VFTD closes as the energetic barrier for the closed conformation decreases. The closed conformation is, however, not very stable and the VFTD can open easily again.

How can IMP bind?

L-glutamate binds. The closed conformation facilitates interactions between the upper and lower lobe and allows binding of IMP. The IMP stabilizes the closed conformation of the VFTD and effectively locks this domain.
The negatively charged phosphate group on IMP coordinates the positively charged amino acid residues in the lobe of the VFTD

Why is IMP an allosteric modulator?

It influenced the L-Glu response by binding at a different site as L-Glu. IMP does not give a response on its own, but indirectly increases the umami perception by L-Glu.

What are GMP and IMP?

Nucleotide-based molecules that can enhance the response of L-Glu and therewith umami perception.
They are ribonucleotides originating from RNA, molecules consisting of a purine base, a ribose and a phosphate group

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Chemical aspects

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