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Complexation of trypsin and alcohol dehydrogenase with poly(diallyldimethylammonium chloride)
Author(s) -
Xia Jiulin,
Mattison Kevin,
Romano Vincent,
Dubin Paul L.,
Muhoberac Barry B.
Publication year - 1997
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/(sici)1097-0282(19970405)41:4<359::aid-bip1>3.0.co;2-l
Subject(s) - chemistry , trypsin , coacervate , chymotrypsinogen , titration , quenching (fluorescence) , fluorescence , alcohol dehydrogenase , chromatography , titration curve , inorganic chemistry , alcohol , biochemistry , chymotrypsin , enzyme , physics , quantum mechanics
Complexation of alcohol dehydrogenase (ADH) and trypsin with poly(diallyldimethyl‐ammonium chloride) (PDADMAC) in dilute electrolyte solution was studied by turbidimetric titration, quasi‐elastic light scattering (QELS), and electrophoretic light scattering (ELS). Both QELS and turbidimetric titration show that PDADMAC forms complexes with ADH and trypsin in 0.01M NaCl solution at pH ≥ 6.8 and pH ≥ 9.2, respectively. These complexes take the form of stable coacervates in 0.01M, pH 11.0, phosphate buffer solution. QELS shows sizes of 400 and 315 nm for the coacervates of ADH‐PDMDAAC and trypsin‐PDMDAAC, respectively, while ELS reveals that these coacervates carry a net positive charge. Activity measurements show that both ADH and trypsin are enzymatically active in their coacervated states. Complexation of trypsin and PDADMAC was also studied by fluorescence in 0.01M, pH 11.0, phosphate buffer, and the protein emission was found to be quenched by complexation. The fluorescence quenching data show that trypsin retains its three‐dimensional structure in the complex. These and other results are consistent with the quenching of the two tryptophans on the protein surface, but not the interior ones.© 1997 John Wiley & Sons, Inc.