Abstract
INFORMATION regarding soy-bean enzymes catalysing the breakdown of starch is contradictory or at best conjectural. The biological function of amylases in soy-beans is obscure as the beans contain very little-starch. The consensus of opinion seems to be that soy-bean seeds are a good source of β-amylase. While some workers1–3 feel that soy-beans contain no or only traces of α-amylase, Teller's investigations4 and evidence from the effects of soy-flour on starch-viscosity measurements5–7 point to the presence of a starch-liquefying enzyme in non-germinated soy-beans. Recently8, the presence of a starch-liquefying and of a starch-saccharifying enzyme in soy-flour was demonstrated by differential thermal inactivation. This communication deals with the effect of the SH-blocking reagent N-ethylmaleimide-(NEMI) on the starch-hydrolysing enzymes of soy-flour. It is known9 that none of the α-amylase so far investigated contains free sulphydryl groups essential for enzymatic: activity. β-Amylase purified and crystallized from soy-beans has been reported10 to contain —SH groups essential for enzymatic activity.
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POMERANZ, Y., MAMARIL, F. Effect of N-Ethylmaleimide on the Starch-liquefying Enzyme from Soy-flour. Nature 203, 863–864 (1964). https://doi.org/10.1038/203863a0
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DOI: https://doi.org/10.1038/203863a0
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