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: EC:3.4.22.32 (
bromelain
)
1,025
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
2,2,2-
Trifluoroethanol
(
TFE
) denatures proteins but also stabilizes/induces alpha helical conformation in partially/completely unfolded proteins. As reported earlier from this laboratory,
stem bromelain
is known to exist as a partially folded intermediate (PFI) at pH 2.0. The effect of increasing concentration of
TFE
on the PFI of
bromelain
has been investigated by circular dichroism (CD), fluorescence emission spectroscopy, binding of the hydrophobic dye 1-anilino 8-naphthalene sulfonic acid (ANS), and near-UV CD temperature transition. Far-UV CD spectra show considerable accumulation of secondary structure at 70% (v/v) concentration of
TFE
with spectral features resembling the pH 7.0 preparation. Interestingly the partially folded intermediate regained significant tertiary structure/interactions, with increasing concentration of
TFE
, and at 60% (v/v)
TFE
approached almost that of the pseudo native (pH 7.0) state. Further increase to 70% (v/v)
TFE
, however, resulted in complete loss of tertiary structure/interactions. Studies on tryptophan fluorescence also suggested the induction of some compact structure at 60% (v/v) concentration of
TFE
. The partially folded intermediate showed enhanced binding of the fluorescent probe (ANS) in the presence of 60% (v/v)
TFE
. Taken together these observations suggest a "molten globule" state between 60 and 70% (v/v)
TFE
. Thermal transition studies in the near-UV CD region indicated cooperative transition for PFI in the presence of 60% (v/v)
TFE
changing to noncooperative transition at 70% (v/v)
TFE
. This was accompanied by a shift in the midpoint of thermal denaturation (T(m)) from 58 to 51 degrees C. Gradual transition and loss of cooperative thermal unfolding in the 60-70% (v/v) range of
TFE
also support the existence of the molten globule state.
...
PMID:Trifluoroethanol-induced "molten globule" state in stem bromelain. 1272 17
