Probing the confinement of β-galactosidase into meso-macro porous silica by Raman spectroscopy

A comprehensive study of protein–mesoporous–macroporous silica interactions by extended canonical variate analysis of Raman spectra

“…These changes can also be related to the type of support employed for the immobilization process (hierarchical silica support with 200 nm of macropore and 9 nm of mesopores size) and the quaternary structure of the β ‐galactosidase from K. lactis (monomer/dimer/tetramer). Prazeres et al, in a similar system, mentioned that the monomers or dimers adsorb into the mesopores and the tetramers into the macrospores, demonstrating a selective absorption into the MMS support. And, due to the higher positively charge and surface area of the dimer structure, an enhanced electrostatic attraction occurs with the MMS support, leading to increased enzyme conformational changes.…”

“…This in turn, is related to the degree of protein surface coverage on the support used. Theoretically, the more enzyme concentration is used for the immobilization process, the higher the surface coverage of the MMS support, [42] CH 3 str [37] 2,888 (+6) 2,888 (+6) 2,885 (+3) 2,885 (+3) --2,882 CH 3 str, R 3 CH str, [42] CH str [37] ----2894 (−3) 2,897 -CH 2 str, [37,43] R 3 CH str [42] 2,906 2,906 -----CH 2 str [37] ----2,940 (+9) 2,931 -CH 2 str, [42] CH 3 str [37] 2,937 2,934 (−3) 2,937 2,937 --2,937 CH 2 str, [42] CH str [37] ---2,965 2,965 2,965 -CH 3 str, str α-CH [42] 2,968 2,965 (−3) ----2,968 CH 3 str, [37,42] str α-CH [ [37] CC str [43] [26] CN str, [16] Tyr, Trp, Phe, Leu [44,46,51] as evidenced by the adsorbed enzyme values given in Section 2.1. Different authors [14] mention that in higher surface coverage (MMS_β-gal_C and MMS_β-gal_C/2), the protein-protein interactions have a much greater influence in comparison with protein-support interactions.…”

“…Next, the samples were washed with buffer solution and kept in a desiccator to dry at room temperature for further analysis. The absorbed β ‐gal (milligram per square meter) into the MMS was determined by UV‐Vis as being: 16 (MMS_ β ‐gal_C), 10 (MMS_ β ‐gal_C/2), and 5.2 (MMS_ β ‐gal_C/10 and (MMS_ β ‐gal_C/20), respectively …”

“…The absorbed β-gal (milligram per square meter) into the MMS was determined by UV-Vis as being: 16 (MMS_β-gal_C), 10 (MMS_β-gal_C/2), and 5.2 (MMS_β-gal_C/10 and (MMS_β-gal_C/20), respectively. [37]…”

High performance biocatalyst based on β-d-galactosidase immobilized on mesoporous silica/titania/chitosan material

“…The highest relative activity loss after the first hydrolysis cycle observed for SiTienz can be attributed to the existence of covalent as well as weak enzyme-silica/titania surface interactions, which lead to partial enzyme leaching. This leaching suggests the existence of non-covalent type interactions, such as weak physical enzyme adsorption, that can be favored by the enzyme entrapment into the pores (Ghannadi, Abdizadeh, Miroliaei, & Saboury, 2019;Prazeres et al, 2019). These conversion values were considered as 100% of the relative activity.…”