Detection and partial characterization of two antigenically distinct β-amylases in developing kernels of wheat.

A β-amylase (EC 3.2.1.2) was identified in the outer pericarp (βP) of developing seeds of wheat (Triticum aestivum L.) and compared with the well known β-amylase which is synthesized during seed development in the starchy endosperm (βE). The enzyme βP already exists in the tissues before anthesis and vanishes at the time when βE starts to accumulate. The isoelectric-focusing patterns of βP and βE are very similar. The relative molecular weight (Mr) of βP is slightly higher than that of βE (66 and 64.5 kDa, respectively). Both βP and βE exhibit common epitopes in addition to epitopes specific for each of them. The two enzymes were identified in small amounts in the green tissues of the developing seeds (inner pericarp and testa). No antigenic difference was detected between βP and the β-amylases of roots and leaves.