Lipoxygenase barley

SUBSTRATE SPECIFICITY OF BARLEY LIPOXYGENASE ISOENZYMES Purification oflox-1 and lox-2... 

In 1886 the use of malted barley flour was mentioned for use in breadmaking. The enzymes in the malt converted starch into sugars which could serve as yeast substrate during fermentation. Almost 50 years later, the use of a purified enzyme (lipoxygenase) was described for bleaching the cmmb of bread. Since then enzyme usage has become widespread in food applications. 

EXPRESSION AND SUBSTRATE SPECIFICITY OF LIPOXYGENASE ISOENZYMES EMBRYOS OF GERMINATING BARLEY... 

Figure 1. Time course of lipoxygenase activity in the embryo of barley upon germination. The ratio of 9- and 13-HPOD formed from linoleic acid by extracts from barley embryos is indicated within the bars.

Doderer A., KokkelinkL, van der Veen S., ValkB.E., Schram A.W. and Douma A.C. (1992) Purification and characterization of two lipoxygenase isoenzymes from germinating barley, Biochim. Biophys. Acta 1120, 97-104. 

Holtman W.L., van Duijn G., Sedee N.J.A. and Douma A.C. (1996) Differential expression of lipoxygenases isoenzymes in embryos of germinating barley. Plant Physiol. Ill, 569-576. 

Hugues M., Boivin P., Gauillard F., Nicolas J., Thiry J-M and Richard-Forget F. (1994) Two lipoxygenases from germinating barley-heat and kilning stability, J. Food Sci. 59 (4) 885-889. 

Yang G., Schwarz P.B. and Vick B. A. (1993) Purification and characterization of lipoxygenase isoenzymes in germinating barley, Afti. Assoc. Cereal Chem. 70 (5) 589-595. 

Expression and Substrate Specificity of Lipoxygenase Isozymes from Embryos of Germinating Barley. 

JASMONATE- AND STRESS-INDUCED LIPOXYGENASE FORMS IN BARLEY LEAF SEGMENTS (HORDEUM VULGARE CV. SALOME)... 

Barley leaf segments respond to the application of (-)-jasmonic acid (JA) or its methylester (JM) as well as to several stress conditions like osmotic stress with the synthesis of so called jasmonate induced proteins (JIPs). Among these proteins is a thionin of 6 kDa, and a protein of 23 kDa with yet unknown function [1]. Beside these results we present evidence on the specific induction of lipoxygenase (LOX) forms in barley leaf segments by jasmonate or by osmotic stress conditions, like incubation with 1 M sorbitol. 

In barley grains, lipoxygenase has been well characterized and two isoenzymes have been purified [1-3] but the characterization of hydroperoxide-metabolizing enzymes has received less attention. Hydroperoxide-consuming enzymes can be divided into two types of enzymes. Hydroperoxide lyase cleaves fatty acid hydroperoxides into aldehydes and oxoacids, and hydroperoxide dehydrase (also named hydroperoxide isomerase) catalyzes the formation of a-and 7-ketols. 

Van Aarle PGM, De Barse MMJ, Veldink GA, Vliegenthart JFG. Purification of a lipoxygenase from ungerminated barley. Characterization and product formation. FEBS Lett 1991 280 159-62. 

Schwarz PB, Pyler RE. Lipoxygenase and hydroperoxide isomerase activity of malting barley. 

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