Optimised approach to albumin–drug conjugates using monobromomaleimide-C-2 linkers

Abstract

Conjugation of therapeutics to human serum albumin (HSA) using bromomaleimides represents a promising platform for half-life extension. We show here that the Cys-34 crevice substantially reduces the rate of serum stabilising maleimide hydrolysis in these conjugates, necessitating reagent optimisation. This improved reagent design is applied to the construction of an HSA-paclitaxel conjugate, preventing drug loss during maleimide hydrolysis.Scheme 1 Previous work describing monobromomaleimides for human serum albumin (HSA) conjugation. 13 † Electronic supplementary information (ESI) available. See

One-pot thiol–amine bioconjugation to maleimides: simultaneous stabilisation and dual functionalisation

“…To overcome these limitations we, and others, have reported extensively on the use of dibromomaleimides (DBMs), [16][17][18][19][20][21][22][23] and related substituted maleimides known collectively as next generation maleimides (NGMs). 20,24 These reagents retain the favourable kinetics of maleimides 25,26 whilst avoiding the formation of stereoisomers, and through the addition of two thiols allow the construction of dual conjugates (Fig. 1B).…”

Rapid and robust cysteine bioconjugation with vinylheteroarenes

“…Human serum albumin (HSA) is the most abundant protein found in plasma, which has also been utilised as a biomacromolecular delivery system in protein-drug conjugates. 56 Among the 35 cysteines encoded in the HSA peptide sequence, 34 are present as disul-de bonds; one cysteine (Cys34) is found unpaired. Thus, HSA was deemed to be an ideal substrate to commence protein modication investigations.…”

Employing defined bioconjugates to generate chemically functionalised gold nanoparticles for in vitro diagnostic applications

“…Though the use of site-selective chemistries (e.g., cysteine-selective) would provide a more homogenous product, the lack of readily available reaction sites drastically reduces the potential degree of functionalisation. 24 The optimised protocol granted BSA with TCO:BSA ratios of between approximately 1:1 and 33:1, as determined by MALDI (Fig. S1).…”