3.4.22.52 Ba2+ activates 643987 3.4.22.52 Ba2+ activates, Ka: 1.5 mM 643988 3.4.22.52 Ca2+ - 643983, 643987, 696451 3.4.22.52 Ca2+ 0.0044 mM required for half-maximal activity 679332 3.4.22.52 Ca2+ 0.01 mM 679333 3.4.22.52 Ca2+ activates 707364 3.4.22.52 Ca2+ activates at 1.0 mM 707398 3.4.22.52 Ca2+ activation of mu-calpain requires micromolar calcium (0.4 mM used in assays) 717201 3.4.22.52 Ca2+ activity is absolutely dependent on calcium 709887 3.4.22.52 Ca2+ Ca2+ requirement for half-maximal activation (0.003-0.05 mM) 709681 3.4.22.52 Ca2+ calcium-dependent cysteine protease 708416 3.4.22.52 Ca2+ calcium-dependent, increase of amount of bound calpain 1 by calcium binding to titin 696290 3.4.22.52 Ca2+ calpain 1 is activated by micromolar calcium concentrations 717053 3.4.22.52 Ca2+ calpain I is a calcium-dependent protease 708434 3.4.22.52 Ca2+ calpain1 is a calcium ion-dependent cysteine protease 707296 3.4.22.52 Ca2+ dependent on 707936, 708442, 708717, 708892, 709640, 710087, 717453, 718111, 718386, 731222, 731848, 731906, 752801 3.4.22.52 Ca2+ dependent on (0.002-0.02 mM). At resting [Ca2+], mu-calpain is present predominantly in its full-length, unautolysed/unactivated forms. Once activated, mu-calpain appears in its autolysed form. Endogenously expressed mu-calpain is activated within a physiological [Ca2+] range in a Ca2+- and time-dependent manner. Autolysed mu-calpain isoforms have a greater Ca2+ sensitivity than the full-length 80000 Da isoform 708194 3.4.22.52 Ca2+ dependent on, 100% activity at concentrations higher than 0.04 mM 732676 3.4.22.52 Ca2+ dependent on, dysfunctional mitochondria increase cytosolic calcium, thereby inducing calpain activation 710069 3.4.22.52 Ca2+ dimeric calpain I requires 0.002 mM for half-maximal activation and 0.01 mM for maximal activation. The 70000 Da monomeric calpain I requires only 0.001 mM Ca2+ for half-maximal activity 643981 3.4.22.52 Ca2+ half-maximal activation at 0.002 mM, full activity at 0.01 mM 643987 3.4.22.52 Ca2+ half-maximal activation at 0.0028 mM, maximal activation at 0.01 mM 643983 3.4.22.52 Ca2+ half-maximal activation at 0.008 mM, maximal activation at 0.02 mM 643982 3.4.22.52 Ca2+ half-maximal activation at 0.01 mM 643986 3.4.22.52 Ca2+ half-maximal activation at 0.03 mM, maximal activation at 0.1 mM 643980 3.4.22.52 Ca2+ half-maximal activation at 0.04 mM 643977 3.4.22.52 Ca2+ half-maximal activity at 0.02 mM, maximal activity at 0.1 mM 643979 3.4.22.52 Ca2+ half-maximal activity at 0.04 mM, maximal activity at 0.1 mM 643967 3.4.22.52 Ca2+ incubation with 5 mM Ca2+ results in the activation of micro-calpain 708435 3.4.22.52 Ca2+ Ka-value : 0.05 mM 643988 3.4.22.52 Ca2+ Kd-value: 0.025 mM. 25% of the difference in Kd values between mu- and m-calpain can be ascribed to the N-terminal peptide of the large subunit, whereas the C-terminal EF-hand-containing domain IV accounts for 65% of the difference 643968 3.4.22.52 Ca2+ maximal activation at about 0.002 mM 643989 3.4.22.52 Ca2+ micromolar (0.005-0.05 mM) Ca2+ concentrations are required for activation in vitro 707559 3.4.22.52 Ca2+ mu-calpain is activated by neuronal stimulation and Ca2+-influx 678984 3.4.22.52 Ca2+ mu-calpain is autolytically activated at micromolar Ca2+, mice muscle fibers that are partially excitation-contraction uncoupled by exposure to 0.005 mM Ca2+ for 3 min (no ATP) show the presence of autolytic activation of a proportion of the human mu-calpain present 707053 3.4.22.52 Ca2+ mu-calpain is freely diffusible in the cytoplasm at resting Ca2+ concentrations but binds within seconds at high Ca2+ concentrations. Ca2+ concentration has to be raised to above 0.002 mM for more than 1 min to initiate detectable autolysis of mu-calpain and to activate appreciable proteolytic activity. If Ca2+ concentration is raised sufficiently for long enough to initiate substantial autolysis of mu-calpain, the Ca2+ sensitivity of the proteolytic activity is greatly increased and it remains active even at 300 nM Ca2+, with activity only ceasing if the Ca2+ concentration is decreased to about 50 nM Ca2+ 670009 3.4.22.52 Ca2+ needed for enzyme activation 731990 3.4.22.52 Ca2+ required 708051 3.4.22.52 Ca2+ required for activity 708257 3.4.22.52 Ca2+ requires 0.053 mM Ca2+ for half-maximal activity. Activation by Ca2+ promotes the separation of the two subunits of the expressed recombinant protein 643976 3.4.22.52 Ca2+ requires a micromolar concentration of Ca2+ for activity 707065 3.4.22.52 Ca2+ requires a micromolar concentration of calcium ions 707531 3.4.22.52 Ca2+ sensitive to the frequency of fast Ca2+ oscillations in vitro 643997 3.4.22.52 Ca2+ the enzyme is Ca2+-dependent 707281 3.4.22.52 Ca2+ the enzyme requires micromolar calcium concentrations for activation 709641 3.4.22.52 Ca2+ the enzyme requires micromolar levels of Ca2+ for half-maximal activation 708018 3.4.22.52 Ca2+ the primary event in Ca2+-activation corresponds to the binding of Ca2+ to eight interacting sites, of which are four in each of the two calpain subunits. Progressive binding of the metal iuon is linearly correlated with the dissociation of the proteinase, which reaches completion when all eight binding sites are occupied. The affinity for Ca2+ in the native heterodimeric calpain is increased 2fold in the isolated 80000 Da catalytic subunit, but it reaches a Kd-value consistent with the physiological concentration of Ca2+ only in the active autoproteolytically derived 75000 Da form. Binding of the Ca2+ in physiological conditions, and thus the formation of the 75000 Da subunit, can occur only in the presence of positive modulators, the natural activator protein or highly digestible substrates. As a result, both dissociation into the constituent subunits and the autoproteolytic conversion of the native 80000 Da subunit into the active 75000 Da subunit form can occur within the physiological fluctuations in Ca2+ concentrations 643975 3.4.22.52 Mn2+ 0.1 mM, less than 10% as active as Ca2+ 643979 3.4.22.52 Mn2+ activates 643987 3.4.22.52 Mn2+ slight activation 643988 3.4.22.52 Mn2+ synergistic acivation in combination with Ca2+ 643967 3.4.22.52 Sr2+ 0.1 mM, less than 10% as active as Ca2+ 643979 3.4.22.52 Sr2+ activates 643987 3.4.22.52 Sr2+ activates, Ka: 0.45 mM 643988 3.4.22.52 Sr2+ synergistic acivation in combination with Ca2+ 643967