ScienceAsia 21 (1995): 283-292 |doi: 10.2306/scienceasia1513-1874.1995.21.283

AGGREGATION OF CASSAVA LINAMARASE

KANNIKA SERMSUVITYAWONG,¹ M.R. JISNUSON SVASTI,^1,2 PHANEE SAWANG-AREETRAKUL,^1,2 PENNAPA KISAMANONTA¹ AND MONTRI CHULAVATNATOL¹

ABSTRACT: Cassava linamarase was studied by chromatographic and electrophoretic techniques. Repeated chromatography on Sepharose 4B suggested that linamarase could form large aggregates of 600,000 to 2,000,000 daltons, which did not readily equilibrate with each other. Polyacrylamide electrophoresis under denaturing conditions employing sodium dodecyl sulfate, acid-urea or triton-acid-urea suggested that the linamarase enzyme consisted of a single type of subunit. However, aggregation was also observed by non-denaturing polyacrylamide gel electrophoresis, and the sizes of aggregates were determined as containing 4, 6, 8, 10, 12-14 subunits and larger. Moreover, aggregates of different sizes could afsobe observed in freshly prepared extracts, so that aggregation might be present in vivo and play some role in the action of the enzyme. The aggregates did not dissociate in the presence of sodium dodecyl sulfate or -mercaptoethanol unless heated

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1 Department of Biochemistry, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand.
2 Laboratory of Biochemistry, Chulabhorn Research Institute, Vibhavadee Rangsit Road, Bangkok 10210, Thailand.

Received August 14, 1995