| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1995: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1994: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Research Abstract |
Aldchyde oxidase (AO) has been extensively in vestigated in animals and microorganisms. Inplants, however, there has been only a limited information on this enzyme. A great interest in this enzyme has been in its possible involvement in IAA synthesis, but its function in IAA biosynthesis is not presently known. We have suggested that major portion of IAA was synthesized from tryptophan in maize coleoptile, and have also found an in vitro system for formation of IAA from tryptophan in extracts of coleoptiles. In the present study, we purified AO from maize coleoptiles and tried to get cDNA clone (s). The summary of the results are as follows :
(1) From coleoptiles of 3-day-old maize seedlings, aldehyde oxidase (AO) was purified around 2,000-fold. The enzyme was an approximately 300 kDa homodimer composed of two 150 kDa subunits. It contained FAD,molybdenum and iron as prosthetic groups ; the presence of FAD and the metals in plant AO was demonstrated for the first time.
(2) Besides IAA1d, other aromatic aldehydes such as indole-3-aldehyde and benzaldehyde served as good substrates. Immunoblotting analysis with mouse polyclonal antibodies against the purified maize AO showed that the enzyme was relatively rich in the apical region of maize coleoptile.
(3) From the purified enzymes, partial sequences of amino acid were determined. Next, using PCR methods some cDNA segments were obtained. Now, we have 2 species of 4kb cDNA clones (may be full length) and are continuing to determine the sequences. Both clones are highly homologue to bovine aldehyde oxidase and animal xanthine dehydrogenases. The sequences obtained here are reported first in plants.
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