Purification and partial amino acid sequence of human urine protein 1. Evidence for homology with rabbit uteroglobin.

We describe the purification of Urine Protein 1 (UP1), a 14-16 kDa protein which occurs in the urine of patients with renal failure, and therefore may originate from the plasma or kidney. Amino acid sequencing shows that UP1 has significant homology with rabbit uteroglobin, a secretory protein of the uterus (during pregnancy) and lungs (both sexes), and previously identified only in lagomorphs (rabbits, hares, pikas). The finding of a human uteroglobin-like protein, which can be purified from a readily available source, may provide further opportunities to elucidate the, as yet, uncertain physiological functions of uteroglobin.