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Rice aspartic proteinase, oryzasin, expressed during seed ripening and germination, has a gene organization distinct from those of animal and microbial aspartic proteinases
- Asakura, T., Watanabe, H., Abe, K., Arai, S.
- European journal of biochemistry 1995 v.232 no.1 pp. 77-83
- Oryza sativa, seeds, aspartic proteinases, structural genes, complementary DNA, clones, nucleotide sequences, amino acid sequences, ripening, seed germination, gene expression
- The gene organization and nucleotide sequence of an aspartic proteinase (AP) of plant origin were first disclosed by cDNA and genomic DNA cloning of a rice AP (oryzasin). The deduced amino acid sequence of oryzasin 1 was significantly similar to those of other APs (34-85%), with highest similarity (85%) to barley AP (HvAP). Oryzasin 1, as well as HvAP, is distinct from animal and microbial APs in that the plant APs contain a unique 104-amino-acid insertion in the C-terminal region. The oryzasin 1 gene spans approximately 6.6 kbp and is composed of 14 exons and 13 introns. The exon-intron organization of the oryzasin 1 gene is totally different from those of genes for animal and microbial APs such as human cathepsin D, rat renin, bovine chymosin, aspergillopepsin A of Aspergillus awamori, proteinase A of Saccharomyces cerevisiae and rhizopuspepsin of Rhizopus niveus, despite the fact that oryzasin 1 shows overall sequence similarity to these APs.