Y. Uraki, A. Hanzaki, K. Hashida, Y. Sano
Self-Assembly of Pulp Derivatives as Amphiphilic Compounds: Verification of Molecular Association and Complexation with Low and High Molecular Mass Compounds
Summary
Acetic acid pulps (AAPs) have been converted to amphiphiles by hydroxypropylation. The resulting
hydroxypropyl derivatives (HP-AAPs) formed self-aggregates in water. The interaction of HP-AAP molecules
was investigated by a viscometric method. The reduced viscosity (?sp/c) of HP-AAP in both water
and chloroform was increased remarkably above a concentration of 0.1%. This implies that HP-AAP
molecules strongly interact with each other, caused by the hydrophobic interaction of residual lignins in
water and by hydrogen bonding of polysaccharides in chloroform. The self-aggregates adsorb water-soluble
fluorescent agents. The highest adsorption capacity was observed at the lowest pH among three pH
conditions investigated. They also solubilized sparingly water-soluble fluorescent agents in water in larger
amounts than did sodium dodecyl sulfate when used as a surfactant. These results suggest that the self-aggregates
of HP-AAP adsorb low molecular mass compounds as inclusion compounds. To clarify the
interaction of HP-AAP with biopolymers as high molecular mass compounds, the change in the activity
of papain, a protease, in phosphate buffer (pH 6.2) was examined in the presence and absence of HP-AAP.
HP-AAP acted as an inhibitor of papain at the initial stage of mixing. After mixing for 24 hours,
however, the papain activity was revived and preserved for 6 days. In contrast, the papain activity vanished
in the absence of HP-AAP after 24 hours because of autolysis. Therefore, HP-AAP protects papain
against autolysis, resulting from tight complexation with the biopolymer.
Holzforschung, Walter de Gruyter
Print ISSN: 0018-3830
Volume: 54, 09/2000
Pages: 535 - 540
Show full article (external site)
Show all available items of this journal
Search
