Purification and characterization of phycoferritin from the blue-green alga, Arthrospira (Spirulina) platensis |
| |
Authors: | G Lakshmi Deepa R B Sashidhar Vijay Deshpande |
| |
Institution: | (1) Department of Biochemistry, University College of Science, Osmania University, Hyderabad, 500 007, Andhra Pradesh, India |
| |
Abstract: | Phycoferritin from the nutritionally important blue-green alga Arthrospira platensis has been isolated, by application of conventional biochemical techniques. The molecular mass, yield, iron and total neutral
carbohydrate contents of the purified protein were 470 kDa, 0.044 mg g−1 of Arthrospira, 1.4 and 20%, respectively. The iron content was much lower when compared to bacterial and mammalian ferritins. The P: Fe
ratio of Arthrospira phycoferritin was 1: 3.5, a value akin to bacterioferritins. Native gel-electrophoresis revealed the presence of isoforms.
Subunit analysis by SDS-PAGE and Western blotting showed a protein subunit with an apparent molecular mass of 18 kDa. Oligomeric
forms of the protein subunit were also present. The phycoferritin exhibited cross-reactivity with anti-pea seed ferritin suggesting
phylogenetic relationship with that of higher plants. Carbohydrate analysis of phycoferritin by GC-MS revealed the presence
of sugars such as galactose, glucose and mannose similar to that of mammalian ferritins. Interestingly, the analysis also
revealed sugars such as rhamnose, xylose and talose, which has not been reported in the structure of ferritins. Except for
very low histidine content in phycoferritin, the rest of the amino acid composition resembled to ferritins of other species.
UV-visible spectral analysis of the phycoferritin revealed the presence of haem groups, a property characteristic of bacterioferritins.
The fluorescence intensity of phycoferritin was higher than equine spleen ferritin. Circular dichroic spectra revealed a lower
degree of helicity. |
| |
Keywords: | Bacterioferritin Cross-reactivity Ferritin Glycoprotein Haem Subunit |
本文献已被 SpringerLink 等数据库收录! |
|