| Co-Investigator(Kenkyū-buntansha) |
MORISHITA Fumihiro Hiroshima University, Faculty of Science, Research Associate, 大学院・理学研究科, 助手 (20210164)
FUKUKAWA Yasuo Hiroshima University, Faculty of Science, Associate Professor, 大学院・理学研究科, 助教授 (40209169)
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| Research Abstract |
Three Aplysia peptide families were investigated for the functional diversity of their members. (1) Each antibody revealed the presence of immunoreactive cells and fibers in various tissues and organs of Aplysia, suggesting that these family peptides have versatile functions. (2) Effectiveness of the petides on some assay system was different between members of each family. This may indicate the occurrence of functional diversification among the family members. (3) Enzymatic degradation is one of the major inactivation mechanisms for peptides. Stability with the degrading enzymes and bioactivity of fragment peptides formed by the enzyme reactions may be the significant factors bearing functional diversification of the family members. One of the AMRP family members, GAPRFV amide, was degraded differentially by the hemolymph and the ganglionic membrane. A cardioactive D-amino acid-containing peptide, NdWFamide (Asn-D-Trp-Phe-NH_2), was inactivated by the deamidase reaction during incubation with the membrane preparation, but stable in the hemolymph. These results suggest that the mode of peptide degradation depends on their mode of action, neurotransmitters or humoral factors. It will be necessary to assess the possibility that the occurrence of multiple family peptides, their posttranslational modifications, and the mode of degradation may contribute to functional diversification of peptides.
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