Rabbit Anti-Human Calbindin D28K monoclonal antibody for ICC, IF, WB. Calbindin-D-28K (also termed vitamin D-dependent calcium-binding protein, or cholecalcin), is a highly conserved 28kDa calcium binding protein, with broad tissue distribution. It belongs, together with calmodulin, S-100, parvalbumin, troponin C and other proteins, to a family of low molecular weight calcium-binding proteins (CaBPs). These CaBPs have homologous primary structures, which contain conserved polypeptide folds of the EF-hand type for Ca2+ binding. Calbindin-D-28K is found predominantly in subpopulations of central and peripheral nervous system neurons, and in certain epithelial nervous system neurons, and in certain epithelial cells involved in Ca2+ transport such as distal tubular cells and cortical collecting tubules of the kidney, and in enteric neuroendocrine cells.