Literature summary for 3.4.22.52 extracted from

Michetti, M.; Salamino, F.; Minafra, R.; Melloni, E.; Pontremoli, S.
Calcium-binding properties of human erythrocyte calpain (1997), Biochem. J., 325, 721-726.

No PubMed abstract available

Search for more literature for 3.4.22.52

Metals/Ions

Metals/Ions	Comment	Organism	Structure
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	Homo sapiens

Organism

Organism	UniProt	Comment	Textmining
Homo sapiens	-	-	-

Source Tissue

Source Tissue	Comment	Organism	Textmining
erythrocyte	-	Homo sapiens	-

Subunits

Subunits	Comment	Organism
More	Ca2+ causes autoproteolytic conversion of the native 80000 Da subunit into the active 75000 Da subunit	Homo sapiens

Use of this online version of BRENDA is free under the CC BY 4.0 license. See terms of use for full details.

Release 2023.1 (January 2023)