?:abstract
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The surfaces of the polyacrylamide cryogels were coated with L-tryptophan (cryogel-Trp) or L-phenylalanine (cryogel-Phe) to enhance crude leaf extract-derived ora-pro-nobis (OPN) protein binding via pseudo-specific hydrophobic interactions. Cryogels functionalized with amino acids were prepared and characterized through morphological, hydrodynamic, and thermal analyses. The adsorption capacities of cryogel-Phe and cryogel-Trp were evaluated in terms of type (sodium sulfate or sodium phosphate) and concentration (0.02 or 0.10â¯molâL-1) of saline solution, pH (4.0, 5.5, or 7.0), and NaCl concentration (0.0 or 0.5â¯molâL-1). The cryogel-Phe presented a higher adsorptive capacity, achieving its maximum value (qâ¯=â¯92.53â¯mgâg-1) when the crude OPN crude leaf extract was diluted in sodium sulfate 0.02â¯molâL-1â¯+â¯NaCl 0.50â¯molâL-1, at pHâ¯=â¯7.0. The dilution rate significantly (pâ¯<â¯0.05) affected the recovered protein amount after the adsorption and elution processes, reaching 94.45% when the feedstock solution was prepared with a crude extract 5 times. The zeta potential for the eluted OPN proteins was 5.76â¯mV (pHâ¯=â¯3.23) for both dilution rates. The secondary structure composition mainly included ß-sheets (46.50%) and α-helices (13.93%). The cryogel-Phe exhibited interconnected pores ranging 20-300⯵m in size, with a Young modulus of 1.51â¯MPa, and thermal degradation started at 230⯰C. These results indicate that the cryogel-Phe exhibited satisfactory properties as promising chromatography support for use in high-throughput purification of crude leaf extract-derived OPN proteins.
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