Publications by authors named "Hamakubo T"

DEAE-cellulose chromatography of mouse brain extract demonstrated the occurrence of two calpastatin fractions, CS-0.1 and CS-0.2, with distinctly higher content of the latter.

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Pig brain was found to contain two calpain-specific, heat-stable inhibitory fractions which could be separated by DEAE-cellulose chromatography. CS-0.1, which was eluted from the column at 0.

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Calpain I requires low Ca2+ for activation and calpain II requires high Ca2+. It was generally accepted that erythrocytes contain calpain I and calpastatin, but no calpain II. We have recently found, however, that nucleated chicken erythrocytes contain both calpains I and II in addition to calpastatin.

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Degradation of neurofilament (NF) triplet proteins: NF200 (molecular weight (MW) 200,000), NF150 (MW 150,000), and NF68 (MW 68,000) as well as of other cytoskeletal proteins in the rat brain during ischemia was investigated. Sodium dodecyl sulfate-gel electrophoresis and immunoblot methods with anti-NF200 antibody were used for the study. Selective degradation of NF200 and NF150 was observed during the initial 10 to 15 minutes of ischemia.

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Evidence is presented of polymorphonuclear (PMN) cells derived from pig peripheral blood containing two molecular species of Ca2+-dependent cysteine endopeptidases, calpains I and II, which require low and high concentrations of Ca2+, respectively, for activation. Calpains I and II, purified from PMN homogenates, are heterodimers consisting of 83 plus 29 kDa and 80 plus 29 kDa subunits, respectively, which can be identified by using subunit-specific antibodies and which are identical with those of calpain species in other pig tissues and cells hitherto reported. However, a 70-kDa calpain can also be detected when pig PMN cells are disrupted by the nitrogen cavitation method under rather mild conditions, i.

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Chicken erythrocytes were found to contain two species of calpains which differ in elution profile from DEAE-cellulose and in Ca2+ requirement. After partial purification, one of them was half-maximally activated by 10 microM Ca2+ and the other by 180 microM Ca2+. The low- and high-Ca2+-requiring proteases cross-reacted only with the respective monospecific antibodies for mammalian calpain I and calpain II, respectively.

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Calpains I and II are calcium-dependent proteases that have been implicated in several aspects of brain function, including neurofilament turnover, Wallerian degeneration, and excitatory synaptic transmission. In this study, specific affinity-purified antibodies against each of the enzymes were used to determine their cellular distribution in rat brain. Differences between the two were found throughout the brain, with calpain I being located primarily in neurons, whereas calpain II was more prominent in glial cells.

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The biochemical properties and immunohistochemical localization of calpain, a Ca++-dependent, intracellular, nonlysosomal cysteine proteinase was examined in human skin. Human epidermal calpain I was fractionated on a DEAE-cellulose column and was found to be half-maximally activated at 3.5 microM free Ca++ and fully activated at 10 microM Ca++ as measured by casein hydrolysis.

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