Alpha-S1-Casein, or Casein alpha s1, is a human gene encoded by CSN1S1. It may also be known as: Alpha-S1-casein; Casoxin-D; CASA; CSN1. The encoded protein has an amino acid length of 185 and a mass of 21.7 kDa. Alpha-S1-Casein is a member of the Alpha-casein family. Homologs of this gene exist in other organisms, including: Mouse, Rat.