Production of the α and β Subunits of Spirulina Allophycocyanin and C-Phycocyanin in Escherichia coli : A Comparative Study of Their Antioxidant Activities.
Allophycocyanin and c-phycocyanin have been reported to be potent antioxidants. In this work, the genes encoding the apo-proteins of allophycocyanin α (ApcA), allophycocyanin β (ApcB), c-phycocyanin α (CpcA), and c-phycocyanin β (CpcB) from Spirulina platensis were cloned, and the recombinant proteins were produced in Escherichia coli to study their antioxidant effects. All four recombinant phycocyanins could be produced in the soluble form and purified to more than 97% purity. The results of radical scavenging assays showed that the Trolox equivalent values for peroxyl radical scavenging by the ApcA, ApcB, CpcA, and CpcB proteins were 1.81 ± 0.2 µM, 1.98 ± 0.22 µM, 0.95 ± 0.15 µM, and 1.49 ± 0.15 µM, respectively. The IC50 values for hydroxyl radical scavenging of ApcA, ApcB, CpcA, CpcB, and Trolox were 269 ± 9 µg/mL, 190 ± 5 µg/mL, 129 ± 8 µg/mL, 108 ± 4 µg/mL, and 195 ± 12 µg/mL, respectively. These results indicated that allophycocyanin exhibited higher activity than c-phycocyanin in scavenging peroxyl radicals, whereas c-phycocyanin exhibited higher activity than allophycocyanin in scavenging hydroxyl radicals. All of the apo-phycocyanin subunits possessed strong antioxidant activities and can be further developed and applied to the food and drug industries. However, the selection of the most useful antioxidant should depend on the type of targeted free radical to obtain the highest efficiency.
Graduate Program of Clinical Biochemistry and Molecular Medicine, Department of Clinical Chemistry, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok, Thailand.
Thiti
T
Cherdkiatikul
Center for Research and Development in Molecular Hematology Sciences, Department of Clinical Microscopy, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok, Thailand yaneenart@gmail.com.
Yaneenart
Y
Suwanwong
D000975:Antioxidants / Q000737:chemistry*; D002839:Chromans / Q000737:chemistry; D017931:DNA Primers / Q000737:chemistry; D004926:Escherichia coli / Q000378:metabolism; D005609:Free Radicals / Q000737:chemistry; D005822:Genetic Vectors; D017665:Hydroxyl Radical; D020128:Inhibitory Concentration 50; D010100:Oxygen / Q000737:chemistry; D010798:Phycocyanin / Q000096:biosynthesis / Q000737:chemistry*; D010957:Plasmids / Q000378:metabolism; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry; D015203:Reproducibility of Results; D053545:Spirulina / Q000737:chemistry*
D000975:Antioxidants; D002839:Chromans; D017931:DNA Primers; D005609:Free Radicals; D011994:Recombinant Proteins; C002497:allophycocyanin; D010798:Phycocyanin; D017665:Hydroxyl Radical; C010643:6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid; D010100:Oxygen
antioxidant; cloning; phycocyanin; radical scavenging assay