Thiamin pyrophosphokinase 1 (TPK1), belongs to the thiamine pyrophosphokinase family. TPK1 exists as a homodimer, and is detected in heart, kidney, testis, small intestine and peripheral blood leukocytes, and at very low levels in a variety of tissues. TPK1 can catalyze the phosphorylation of thiamine to thiamine pyrophosphate. It can also catalyze the phosphorylation of pyrithiamine to pyrithiamine pyrophosphate.