S-100 protein is a family of low molecular weight protein found in vertebrates characterized by two calcium binding sites of the helix-loop-helix conformation. There are at least 21 different types of S100 proteins. which are involved in regulation of protein phosphorylation, transcription factors, Ca++ homeostasis, the dynamics of cytoskeleton constituents, enzyme activities, cell growth and differentiation, and the inflammatory response. Description: Bovine brain tissue. Alternative Names: S-100, S100, S-100 Protein, S-100 BB Protein, S 100, S-100 protein, S 100 protein