Morphologies and conformation transition of lentinan in aqueous NaOH solution

✍ Scribed by Xufeng Zhang; Lina Zhang; Xiaojuan Xu

• Publisher: Wiley (John Wiley & Sons)
• Year: 2004
• Tongue: English
• Weight: 183 KB
• Volume: 75
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.20112

✦ Synopsis

Abstract

Molecular morphologies and conformation transition of lentinan, a β‐(1→3)‐D‐glucan from Lentinus edodes, were studied in aqueous NaOH solution by atomic force microscopy (AFM), viscometry, multiangle laser light scattering, and optical rotation measurements. The results revealed that lentinan exists as triple‐helical chains and as single random‐coil chains at NaOH concentration lower than 0.05__M__ and higher than 0.08__M__, respectively. Moreover, the dramatic changes in weight‐average molecular weight M~w~, radius of gyration 〈s^2^〉^1/2^, intrinsic viscosity [η], as well as specific optical rotation at 589 nm [α]~589~ occurred in a narrow range of NaOH concentration between 0.05 and 0.08__M__ NaOH, indicating that the helix–coil conformation transition of lentinan was carried out more easily than that of native schizophyllan and scleroglucan, and was irreversible. For the first time, we confirmed that the denatured lentinan molecule, which was dissolved in 0.15__M__ NaOH to be disrupted into single coil chains, could be renatured as triple helical chain by dialyzing against abundant water in the regenerated cellulose tube at ambient temperature (15°C). In view of the AFM image, lentinan in aqueous solution exhibited the linear, circular, and branched species of triple helix compared with native linear schizophyllan or scleroglucan. © 2004 Wiley Periodicals, Inc. Biopolymers, 2004