Proceedings of the Japan Academy, Series B
Online ISSN : 1349-2896
Print ISSN : 0386-2208
ISSN-L : 0386-2208
Volume 87, Issue 6
Displaying 1-3 of 3 articles from this issue
  • Hiroyuki SORIMACHI, Shoji HATA, Yasuko ONO
    2011 Volume 87 Issue 6 Pages 287-327
    Published: June 10, 2011
    Released on J-STAGE: June 13, 2011
    Calpain is an intracellular Ca2+-dependent cysteine protease (EC; Clan CA, family C02) discovered in 1964. It was also called CANP (Ca2+-activated neutral protease) as well as CASF, CDP, KAF, etc. until 1990. Calpains are found in almost all eukaryotes and a few bacteria, but not in archaebacteria. Calpains have a limited proteolytic activity, and function to transform or modulate their substrates’ structures and activities; they are therefore called, “modulator proteases.” In the human genome, 15 genes—CAPN1, CAPN2, etc.—encode a calpain-like protease domain. Their products are calpain homologs with divergent structures and various combinations of functional domains, including Ca2+-binding and microtubule-interaction domains. Genetic studies have linked calpain deficiencies to a variety of defects in many different organisms, including lethality, muscular dystrophies, gastropathy, and diabetes. This review of the study of calpains focuses especially on recent findings about their structure–function relationships. These discoveries have been greatly aided by the development of 3D structural studies and genetic models.

    (Communicated by Masanori OTSUKA, M.J.A.)
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  • Haruo OGURA
    2011 Volume 87 Issue 6 Pages 328-361
    Published: June 10, 2011
    Released on J-STAGE: June 13, 2011
    Sialic acids are electronegatively charged C9-sugars and are considered to play important roles in higher animals and some microorganisms. Denoting their significance, understanding and exploiting the complexity of the sialic acids has been referred to as the “the third language of life”. In essence, “sialic acid derivatives possess a harmonious shape and good balance between two opposing hydrophilic and hydrophobic parts, meaning that they should display various kinds of potentially unique and possibly conflicting physiological activities (glycolipoids)”. Consequently, there are good omens that unprecedented ‘miracle’ medicines could be developed from sialic acid derivatives. In this review, the first problem, the preparation of sialic acids, is covered, the synthesis of sialic acid derivatives and confirmation of their structures obviously being of critical significance. In addition we needed to confirm their precise stereochemistry and a hydrolysis method has been developed for confirmation of the anomeric position. Several of the compounds have already demonstrated interesting bioactivity.

    (Communicated by Satoshi OMURA, M.J.A.)
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