Surfactant Copolymers Prevent Aggregation of Heat Denatured Lysozyme

Abstract

We investigated the ability of certain triblock copolymer surfactant poloxamers of the form polyethylene oxide-polypropylene oxide-polyethylene oxide (PEO-PPO-PEO), to prevent formation of stable aggregates of heat denatured hen egg lysozyme. Differential scanning calorimetry (DSC) and synchrotron small angle x-ray scattering (SAXS) experiments were performed to study the thermodynamics and solution structures of lysozyme at temperatures between 20 and 90°C in the presence and absence of poloxamers with various molecular weights (8.4-14.3 kDa), but similar hydrophile/hydrophobe (PEO:PPO) ratio of 80%. Poloxmer 188 was found to be very effective in preventing aggregation of heat denatured lysozyme and those functioned as a synthetic surfactant, thus enabling them to refold when the conditions become optimal. For comparison, we measured the ability of 8 kDa polyethylene glycol (PEG) to prevent lysozyme aggregation under same conditions. The results of these studies suggest that poloxamers are more efficient than PEG in preventing aggregation of heat denaturated lysozyme, To achieve equivalence, more than an order of magnitude higher concentration of PEG concentration was needed. Apparently, the presence of a hydrophobic segment in the poloxamers increases their ability to target the hydrophobic region of the unfolded proteins and protect them from self association. Given their biocompatibility and the low concentrations at which they effectively facilitate refolding of denatured proteins, they may be useful in the treatment of burns and other conditions resulting in the denaturation of proteins.

Role of a Novel Excipient Poly(ethylene glycol)-b-poly(l-histidine) in Retention of Physical Stability of Insulin at Aqueous/Organic Interface

“…Pluronics are believed to be absorbed to the abnormally exposed hydrophobic regions of the unfolded proteins, alter local hydrophobic interactions as well as alter the local surface tension in such a fashion to facilitate protein disaggregation and refolding. 42 In all systems, PEG-polyHis was more effective in preventing insulin aggregation than F-127. Modest results with F-127 to protect insulin at the interface may be explained on the basis of anomalous behavior of PEG chains at the water-MC interface.…”

The Pentablock Amphiphilic Copolymer T1107 Prevents Aggregation of Denatured and Reduced Lysozyme

“…[3] Because similar forces drive protein aggregation, we hypothesized that P188 also behaved as a synthetic chaperone. Previous investigations have shown that P188 interfered with heat-induced aggregation of lysozyme, [4,5] and subsequent work showed that Macromol. Biosci.…”

Mode of action of poloxamer‐based surfactants in wound care and efficacy on biofilms

“…Mustafi et al found that amphiphilic, surfactant, multi‐block copolymers, such as Poloxamer 108 (P108), Poloxamer 188 (P188), and Tetronic 1107 (T1107) are efficient as additives to suppress aggregation of and to facilitate refolding of heat‐denatured hen egg white lysozyme (HEWL) and bovine serum albumin (BSA) in solution. Additionally, Lee et al demonstrated that poloxamers are more efficient than PEG in preventing aggregation of heat denaturized lysozyme. These findings indicate that copolymer surfactants may be applied to the treatment of burns and other conditions resulting in the denaturation of proteins.…”