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Regulation of maize lysine metabolism and endosperm protein synthesis by opaque and floury mutations.

Azevedo, Ricardo A. and Damerval, Catherine and Landry, Jacques and Lea, Peter John and Bellato, Cláudia M. and Meinhardt, Lyndel W. and Le Guilloux, Martine and Delhaye, Sonia and Toro, Alejandro A. and Gaziola, Salete A and Berdejo, Bertha D. A. (2003) Regulation of maize lysine metabolism and endosperm protein synthesis by opaque and floury mutations. FEBS Journal, 270 (24). pp. 4898-4908. ISSN 1742-464X

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Abstract

The capacity of two maize opaque endosperm mutants (o1 and o2) and two floury (fl1 and fl2) to accumulate lysine in the seed in relation to their wild type counterparts Oh43+ was examined. The highest total lysine content was 3.78% in the o2 mutant and the lowest 1.87% in fl1, as compared with the wild type (1.49%). For soluble lysine, o2 exhibited over a 700% increase, whilst for fl3 a 28% decrease was encountered, as compared with the wild type. In order to understand the mechanisms causing these large variations in both total and soluble lysine content, a quantitative and qualitative study of the N constituents of the endosperm has been carried out and data obtained for the total protein, nonprotein N, soluble amino acids, albumins/globulins, zeins and glutelins present in the seed of the mutants. Following two-dimensional PAGE separation, a total of 35 different forms of zein polypeptides were detected and considerable differences were noted between the five different lines. In addition, two enzymes of the aspartate biosynthetic pathway, aspartate kinase and homoserine dehydrogenase were analyzed with respect to feedback inhibition by lysine and threonine. The activities of the enzymes lysine 2-oxoglutate reductase and saccharopine dehydrogenase, both involved in lysine degradation in the maize endosperm were also determined and shown to be reduced several fold with the introduction of the o2, fl1 and fl2 mutations in the Oh43+ inbred line, whereas wild-type activity levels were verified in the Oh43o1 mutant.

Item Type: Article
Journal or Publication Title: FEBS Journal
Uncontrolled Keywords: lysine metabolism • maize • storage proteins
Subjects: Q Science > QH Natural history > QH301 Biology
Departments: Faculty of Science and Technology > Lancaster Environment Centre
ID Code: 10691
Deposited By: Mr Richard Ingham
Deposited On: 22 Jul 2008 15:10
Refereed?: Yes
Published?: Published
Last Modified: 18 Sep 2013 15:56
Identification Number:
URI: http://eprints.lancs.ac.uk/id/eprint/10691

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