Enzyme-stabilizing activity of seed trypsin inhibitors during desiccation

Seeds contain protective proteins which are able to preserve glucose-6-phos phate dehydrogenase (EC 1.1.1.49) activity upon co-dehydration of the enzym e with heal-stable seed protein extracts. Adenanthera pavonina L. (saga) se ed extracts, in particular, have high levels of enzyme-preserving activity which not only alleviate the detrimental effects of desiccation in the pres ence of Tris-HCl and NaCl, but also stabilize enzyme activity in solution. Purification of Adenanthera seed extracts by reversed-phase and weak anion- exchange perfusion chromatography, followed by N-terminal protein sequencin g have identified Kunitz-type trypsin inhibitors as the major proteins in o ne set of enzyme-preserving fractions. A quantitative comparison using vari ous concentrations of purified proteins has demonstrated that soybean Kunit z trypsin inhibitor is as effective (on a mass basis) as bovine serum album in in preserving enzyme activity, and may be an important protein permittin g enzyme dehydration in a seed undergoing desiccation. (C) 1999 Elsevier Sc ience Ireland Ltd. All rights reserved.