TY  - JOUR
ID  - open515
UR  - http://www.sciencedirect.com/science/article/pii/S0003986110001724
IS  - 1-2
A1  - Dave, Sandeep
A1  - Mahajan, Sahil
A1  - Chandra, Vemika
A1  - Dkhar, H Kitdorlang
A1  - Sambhavi, -
A1  - Gupta, Pawan
N2  - Stem bromelain (SBM), a therapeutic protein, is rapidly absorbed across the gut epithelium. Because SBM encounters an alkaline pH at its principal site of absorption, we investigated the alkaline-induced denaturation of SBM. From pH 7 to 10, the protein's secondary structure remained the same, although a slight loss of tertiary structure was observed. Above pH 10, there was a significant and irreversible loss of secondary and tertiary structure. At pH 10, SBM showed enhanced tryptophan fluorescence, however, the number of accessible tryptophans remained the same. The thermodynamics of temperature transition at pH 7 and 10 were strikingly different, with the former showing a two-phase transition endotherm, and the latter a broad non-two-state transition. At pH 10, SBM showed a significant increase in 8-anilino-1-naphthalene-sulfonate binding relative to the native state, suggestive of a specific molten globule (SMG) state. These studies suggest a distinct conformational rearrangement in SBM, at the protein's isoelectric point.
VL  - 499
TI  - Specific molten globule conformation of stem bromelain at alkaline pH.
AV  - none
EP  - 31
N1  - Copyright of this article belongs to Elsevier Science
Y1  - 2010/07//
PB  - Elsevier Science
JF  - Archives of biochemistry and biophysics
KW  - Protein folding; Alkaline denaturation; Bromelain; Molten globule; Temperature endotherm; Thermodynamics
SN  - 1096-0384
SP  - 26
ER  -