RAPID SEPARATION AND GENOTYPIC VARIABILITY OF BARLEY (HORDEUM-VULGAREL) LIPOXYGENASE ISOENZYMES

Two lipoxygenase (LOX) activities in a crude extract of germinated bar ley were readily resolved by fast protein liquid chromatography (FPLC: ) on a Mono Q HR 5/5 anion-exchange column. Separation was achieved in 25 min, and recovery of activity was consistently greater than 90%. T he two LOX activities were identified as LOX-1 and LOX-2 by isoelectri c focusing and by comparison with the chromatographic properties of pu rified LOS-I and LOX-2. The activities of the two isoenzymes and total LOX activity varied significantly among the cultivars, although the r atio of LOX-1/LOX-2 was fairly constant. Significant variation in LOX activity between cultivars suggests that the LOX activity in malting b arley cultivars might be reduced through breeding. The established sep aration procedure may be useful for screening barley lines for LOX-nul l-allele mutations, and may enhance the prospect of mapping genes that affect LOX activity or levels. (C) 1997 Academic Press Limited