The amino acid sequence of ascorbate peroxidase from tea has a high degree of homology to that of cytochrome c peroxidase from yeast
1992
Chen, G.X. | Sano, S. | Asada, K.
The chloroplast isozyme of ascorbate peroxidase from tea leaves was digested with lysyl endopeptidase, and the amino acid sequences of the peptide fragments were determined. These sequences accounted for 64% of the amino acids in the entire protein. The sequence of one of the peptides can be aligned with the region which includes the proximal histidine that serves as the fifth ligand of the heme iron in guaiacol peroxidases and cytochrome c peroxidase. The sequences of the peptides from ascorbate peroxidase exhibit a higher degree of homology to the sequence of cytochrome c peroxidase from yeast than to those of guaiacol peroxidases from plants. In addition, three of the peptides from ascorbate peroxidase show a high degree of homology to triose-phosphate isomerase from maize. From the available amino acid sequences and the enzymatic and molecular properties of ascorbate and cytochrome c peroxidases, we propose that these hydrogen peroxide-scavenging peroxidases that use either cytochrome c or ascorbate as the electron donor originated from the same ancestral protein.
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