Insight into interactions between enzyme and biological buffers: Enhanced thermal stability of stem bromelain

Pannuru Pavani^a, Krishan Kumar^b, Anjeeta Rani^b,^c, Pannuru Venkatesu^b, Ming-JerLee^a

Department of Chemical Engineering, National Taiwan University of Science and Technology, 43 Keelung Road, Section 4, Taipei 106-07, Taiwan.

Abstract

In the present study, the effect of buffers such as tris(hydroxymethyl)aminomethane (TRIS), N-(tris(hydroxymethyl)methyl)-2-aminoethanesulfonicacid (TES), N-(tris(hydroxymethyl)methyl) -3-aminopropanesulfonic acid (TAPS) on thermal stability of bromelain (BM) have been investigated. The study delineates the influences of TRIS, TES and TAPS onto BM structure using spectroscopic techniques such as UV–visible, fluorescence spectroscopy, Fourier transform infrared spectroscopy (FTIR) and thermal fluorescence spectroscopy. Furthermore, circular dichroism (CD) and dynamic light scattering (DLS) was performed in order to examine structural and size variation in buffer. The results illustrate that among these three buffers, TAPS is the best, TES is mild and TRIS is weakest stabilizer for BM structure. Our results reveal that these three buffers behave as stabilizer for BM. The data from CD and FTIR depict that the buffers slightly perturbed the secondary structure of BM. The present study is useful for providing the alternative media to replace traditional volatile organic compounds for biochemical applications.

Keywords: Biological buffers, Bromelain, Biophysical techniques, Thermal stability, Hydrophobic interactions.