Ready-to-use ELISA kits are available for the detection of GIG13, an alias of the protein, period circadian regulator 3. The official gene symbol is PER3. The protein, with a mass of 131.9 kDa and length of 1201 residues, is reported to be cytoplasmic and nuclear. It may be known by other names, including: FASPS3, period circadian protein 3, hPER3, circadian clock protein PERIOD 3, cell growth-inhibiting gene 13 protein, and period circadian protein homolog 3.