Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: UNIPROT:P01189 (
beta-endorphin
)
21,003
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Spectral and kinetic studies of the interaction of N-methylnicotinamide chloride and nicotinamide with the enzyme thiosulphate sulphurtransferase (thiosulphate: cyanide sulfurtransferase,
EC 2.8.1.1
) (also known as
rhodanese
) have been performed and compared with previous inhibition data obtained with N-1-(4-pyridyl)pyridinium chloride (
NPP
). Like
NPP
both N-methylnicotinamide chloride and nicotinamide are competitive inhibitors of
rhodanese
with respect to the substrate thiosulfate. Rhodanese binding of N-methylnicotinamide chloride gives rise to no charge transfer absorbtion band. In addition, the free energy of interaction (deltaG0) of
NPP
with
rhodanese
is approximately equal to the sum of the individual deltaG0 values of MNA and NA. These compounds are analogous to the two halves of the
NPP
structure. We conclude that
NPP
and N-methylnicotinamide chloride are not bound via a charge transfer mechanism. The major stabilizing influence appears to be an ionic interaction with an anionic enzyme site with accessory apolar stabilization. It is postulated that the ionized active site sulfhydryl group in
rhodanese
could provide the ionic site.
...
PMID:A reexamination of the postulated charge transfer interactions at the active site of the enzyme rhodanese. 13 Sep 34
