Anserine (beta-alanyl-N-methylhistidine) is a dipeptide. Found in the skeletal muscle and brain of mammals, it is an antioxidant and helps reduce fatigue. The pKa of the imidazole ring of histidine, when contained in anserine, is 7.04, making it an effective buffer at physiologic pH (Biochemistry, Garrett & Grisham).