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Antimicrobial, Dehydroascorbate Reductase, and Monodehydroascorbate Reductase Activities of Defensin from Sweet Potato [Ipomoea batatas (L.) Lam. ‘Tainong 57’] Storage Roots
- Source :
- Journal of Agricultural and Food Chemistry. 56:2989-2995
- Publication Year :
- 2008
- Publisher :
- American Chemical Society (ACS), 2008.
-
Abstract
- A cDNA encoding a small cysteine-rich protein designated defensin (SPD1) was isolated from sweet potato storage roots. On the basis of the amino acid sequence similarity and conserved residues, it is suggested that SPD1 is a member of the plant defensin family. Recombinant SPD1 protein overproduced in Escherichia coli was purified by Ni (2+)-chelated affinity chromatography. A recombinant protein from the storage root cDNA clone effectively inhibited the trypsin activity in a dose-dependent manner. Both the corresponding mRNA and protein level were found to be highest in the storage roots, followed by sprout. SPD1 reduced dehydroascorbate (DHA) in the presence of glutathione to regenerate l-ascorbic acid (AsA). However, without glutathione, SPD1 has very low DHA reductase activity, and AsA was oxidized by AsA oxidase to generate monodehydroascorbate (MDA) free radical. MDA was also reduced by SPD1 to AsA in the presence of NADH, mimicking the MDA reductase catalyzed reaction. These data suggest that SPD1 has both DHA reductase and MDA reductase activities. SPD1 was also shown to inhibit the growth of both fungi and bacteria. SPD1 is apparently the first reported plant defensin exhibiting DHA and MDA activities in vitro.
- Subjects :
- DNA, Complementary
Plant defensin
Molecular Sequence Data
Reductase
Biology
medicine.disease_cause
Plant Roots
Defensins
chemistry.chemical_compound
Anti-Infective Agents
Affinity chromatography
Complementary DNA
medicine
NADH, NADPH Oxidoreductases
Amino Acid Sequence
Ipomoea batatas
Escherichia coli
Defensin
Oxidase test
Base Sequence
food and beverages
General Chemistry
Glutathione
Hydrogen-Ion Concentration
chemistry
Biochemistry
Oxidoreductases
General Agricultural and Biological Sciences
Subjects
Details
- ISSN :
- 15205118 and 00218561
- Volume :
- 56
- Database :
- OpenAIRE
- Journal :
- Journal of Agricultural and Food Chemistry
- Accession number :
- edsair.doi.dedup.....655cb9416464b223fc1a9b42f5e001a7