Lysine glutaraldehyde

In another investigation, ELP[V5L2G3-90] with three lysines in the N-terminal region was immobihzed on a glass surface in a microreactor to enable temperature-controlled positioning of ELP fusion proteins. For this purpose, the glass surface was first functionalized with A -2-(aminoethyl)-3-aminopropyltrimethoxysilane, followed by glutaraldehyde treatment and reductive amination to immobilize the biopolymer on the surface (Fig. 17b) [132]. 

A disadvantage of the glutaraldehyde condensation method is that dimers of the hapten and polymers of carrier protein may also form. To overcome this problem, the reaction time is limited to 2-3 h, or an excess of an amine-containing compound, e.g., lysine or cysteamine hydrochloride, is added. A two-step approach also minimizes dimerization. ... 

The reaction of glutaraldehyde with protein carriers and peptide haptens involves mainly lysine e-amine and N-terminal oc-amine groups. The conjugates formed are usually of high-molecular weight and may cause precipitation products. In addition, the orientation of the... 

Hardy, P.M., Nicholls, A.C., and Rydon, H.N. (1976) The nature of the cross-linking of proteins by glutaraldehyde. Interaction of glutaraldehyde with the amino-groups of 6-ami-nohexanoic acid and of b-N-acetyl-lysine. J. Chem. Soc., Perk Trans. 1, 958. 

It is probably the f-amino groups of the proteins lysine residues, that react with glutaraldehyde forming a simple Schiffs base as suggested by Brarmer-Jorgensen (1978). 

The enzymes commonly used as labels in ELISA and other immunochemical reactions include horse radish peroxidase (HRP) and alkaline phosphatase (AP). The enzyme can be covalently coupled to the antibody using glutaraldehyde conjugation to reactive amino groups on the enzyme (lysines) in a phosphate buffered aqueous solution at neutral pH, as shown in Fig. 19 (103). Alternatively, carbohydrates present in the immunoglobulin structure can be cleaved by periodate treatment (see Fig. 20) and bound to free amino groups on the enzyme through a Schiff base reaction (103). 

Kelly et al. [68] L-Lysine Protein samples from milk and pasta L-Lysine a-oxidase/with BSA and glutaraldehyde Ruthenium/rhodium coated glassy carbon electrode covered with 1,2-diaminobenzene polymer/ + 100 mV vs. an Ag/AgCl ... 

The first reported preparation of cross-linked enzyme crystals was by Quiocho and Richards in 1964 [1], They prepared crystals of carboxypeptidase-A and cross-linked them with glutaraldehyde. The material they prepared retained only about 5% of the activity of the soluble enzyme and showed a measurable increase in mechanical stability. The authors quite correctly predicted that cross-linked enzyme crystals, particularly ones of small size where the diffusion problem is not serious, may be useful as reagents which can be removed by sedimentation and filtration. Two years later the same authors reported a more detailed study of the enzymic behavior of CLCs of carboxypeptidase-A [2], In this study they reported that only the lysine residues in the protein were modified by the glutaraldehyde cross-linking. The CLCs were packed in a column for a flow-through assay and maintained activity after many uses over a period of 3 months. 

PM Hardy, AC Nicholls, HN Rydon. Nature of cross-linking of proteins by glutaral-dehyde. 1. Interaction of glutaraldehyde with amino groups of 6-aminohexanoic acid and of a-N-acetyl-L-lysine. J Chem Soc, Perkin Trans I 958-962, 1976. 

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