Dextranol: An inert xeroprotectant

Abstract

Dextranol, a reduced dextran, prevents damage to stored dry protein samples that unmodified dextran would otherwise cause. Desiccation protectants (xeroprotectants) like the polysaccharide dextran are critical for preserving dried protein samples by forming a rigid glass that protects entrapped protein molecules. Stably dried proteins are important for maintaining critical information in clinical samples like blood serum as well as maintaining activity of biologic drug compounds. However, we found that dextran reacts with both dried serum proteins and lyophilized purified proteins during storage, producing high-molecular weight Amadori-product conjugates. These conjugates appeared in a matter of days or weeks when stored at elevated temperatures (37° or 45°C), but also appeared on a timescale of months when stored at room temperature. We synthesized a less reactive dextranol by reducing dextran’s anomeric carbon from an aldehyde to an alcohol. Serum samples dried in a dextranol-based matrix protected the serum proteins from forming high-molecular weight conjugates. The levels of four cancer-related serum biomarkers (prostate specific antigen, neuropilin-1, osteopontin, and matrix-metalloproteinase 7) decreased, as measured by immunoassay, when serum samples were stored for one to two weeks in dextran-based matrix. Switching to a dextranol-based xeroprotection matrix slightly reduced the damage to osteopontin and completely stopped any detectable damage during storage in the other three biomarkers when stored for a period of two weeks at 45°C. We also found that switching from dextran to dextranol in a lyophilization formulation eliminates this unwanted reaction, even at elevated temperatures. Dextranol offers a small and easy modification to dextran that significantly improves the molecule’s function as a xeroprotectant by eliminating the potential for damaging protein-polysaccharide conjugation.

Utilization of Maillard reaction in moist-dry-heating system to enhance physicochemical and antioxidative properties of dried whole longan fruit

“…The impurification of the extracts might have some effect on the protein-stained electrophoretic pattern, resulting in the appearance of a smearing zone of MRPs at HMW on a gel [63]. Moreover, due in part to their increased molecular size of an Amadori product from Maillard reaction, this could cause difficulty in ionizing proteins as well as protein aggregation while running gel [64]. The wide-spread of molecular weight might also attribute to the heterogeneous distribution of SPC components which were a diverse array of protein molecular weight after the moist-dry-heating process.…”

Tip Modification for Interaction Studies Between Polysaccharides and Dental Materials

“…Only at the reducing end and only in the thermodynamically unfavored, open‐chain form of the terminal glucose unit, there is a single reactive aldehyde group (CH=O). [ 37 ] For example, for a 70 kDa dextran with about 432 glucose units, the ratio OH:CH=O is 1296:1. The aldehyde group is, thus, generally difficult to access for solid surface coupling and needs liquid‐phase derivatization beforehand.…”