Cross-linked protein crystals by glutaraldehyde and their applications

Abstract

Cross-linked protein crystal technology, as either a protein stabilisation or enzyme immobilisation method, has garnered more attention recently. This method not only can retain the original activity of the protein molecule but can also significantly enhance the crystals' mechanical and chemical stability. This review presents the preparation and mechanism of cross-linked protein crystals using glutaraldehyde. The mechanical, chemical and thermal properties of the cross-linked protein crystals are also reviewed in detail. In addition, this paper summarises the applications of cross-linked protein crystals in the fields of materials science, biosensors, chromatographic analysis, oral delivery and protein crystal quality improvement. Finally, the limitations and perspectives on cross-linked protein crystals are presented.Crystallisation is a well-known approach to obtain highly puri-ed proteins. During crystallisation, protein molecules can be Fig. 2 A schematic diagram of the polymerisation of glutaraldehyde. 21This journal is

Tuning the mechanical and physicochemical properties of cross‐linked protein films

“…It was observed that the TSM value was the lowest for the 20% GD film. This can be correlated with the type of chemical cross‐links formed by GD with polypeptide chains that results in a change of the solubility of CEPI in water. Initially, GD reacts with the amino acid groups that are easily accessible or present in the outer side of the protein structure.…”

Biotechnological Applications of Proteases in Food Technology

“…Crosslinked enzymes were the first proposal, but the reproducibility was not simple, and enzyme activity losses by chemical modification were significant (Cao and others ; Sheldon ; Ghafourifar and others ). The crosslinked enzyme crystals (CLECs) (Clair and Navia ; Khalaf and others ; St. Häring and Schreier ; Yan and others ) yielded better results, and later the strategy was simplified through the concept of crosslinked enzyme aggregates (CLEAs). CLEAs formation is an immobilization alternative with good acceptance in academia (Cao and others ; Sheldon and others ; Sheldon ; Sheldon, ) (Figure ).…”

Protein crystal based materials for nanoscale applications in medicine and biotechnology

“…Soon after, they demonstrated the enzymatic activity of GA cross‐linked carboxypeptidase‐A crystals in aqueous solutions different from that of the crystallization environment (Quiocho & Richards, ). Since then, aldehydes (Figure a), specifically GA, have been the dominant cross‐linking agents for the stabilization of protein crystals (Cohen‐Hadar et al, ; N. K. Khalaf et al, ; Yan et al, ). Despite the ubiquity of GA cross‐linking, the chemical basis is incompletely understood.…”