Identification of four starch-branching enzymes in barley endosperm: partial purification of forms I, IIa and IIb.

Developing caryopses of barley (Hardeum vulgare L. ev. Golf) were monitored for starch-branching enzyme activity for 1 month after anthesis. Homogenized caryopses from grains with the highest specific activity were used as starting material for purification of branching enzyme by FPLC chromatography. Several branching enzyme activity fractions were resolved. We have previously described the isolation of a 51/50 kDa protein with starch branching activity from one of these fractions. From three other fractions, we have now partially purified starch branching enzymes corresponding to forms I, IIa and IIb.