There are a number of ELISA Kits available for the measurement of KA21, another term for the human protein, keratin 222. Other synonyms may include: keratin-like protein KRT222, keratin 222 type II, keratin-222 pseudogene, and KA21. It is encoded by the KRT222 gene to yield a protein 295 amino acids in length and 34.2 kDa in size. However, there are up to 2 reported isoforms. The protein is categorized into the Intermediate filament family. Versions of KA21 are present in other organisms, including: Mouse, Rat, Zebrafish, Frog.