protein S100-A1; S100 Ca+2-binding protein A1; S-100 protein subunit alpha; S-100 protein alpha chain (S100A1, S100A)

Function

• weakly binds Ca+2
• binds Zn+2 very tightly
• distinct binding sites with different affinities exist for both Ca+2 & Zn+2 on each monomer
• physiological concentrations of K+ antagonize binding of both Ca+2 & Zn+2, especially affecting high-affinity Ca+2-binding sites

Structure

• dimer of either 2 alpha chains, or 2 beta chains, or 1 alpha & 1 beta chain
• belongs to the S-100 family
• contains 2 EF-hand domains

Compartment

cytoplasm

Expression

• highly prevalent in heart
• also found in lesser quantities in skeletal muscle & brain

More general terms

• S100 Ca+2-binding protein A

Component of

• S100 Ca+2-binding protein

Database

• UniProt: http://www.uniprot.org/uniprot/P23297.html
• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=6271
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:6271
• OMIM: https://mirror.omim.org/entry/176940