Period circadian protein homolog 2 (PER2)

Transcriptional repressor which forms a core component of the circadian clock. The circadian clock, an internal time- keeping system, regulates various physiological processes throughout the creation of approximately 24 hour circadian rhythms in gene expression, which are translated to rhythms in behavior and metabolism.

It's derived from the Latin roots'circa' (about) and'diem' (day) and acts as an important regulator of a wide array of physiological functions such as metabolism, sleep, body temperature, blood pressure, endocrine, immune, cardiovascular, and renal function. Consists of two major elements: the central clock, residing in the suprachiasmatic nucleus (SCN) of the brain, along with the peripheral clocks which are found in nearly every tissue and organ system.