Characterization of a unique nonsecretory ribonuclease from urine of pregnant women.
We have reported previously [Sakakibara, et al. (1991) Chem. Pharm. Bull. 39, 146-149] that a protein purified from a partially purified pharmaceutical preparation of human chorionic gonadotropin (a urinary protein preparation from pregnant women) is a unique nonsecretory ribonuclease (RNase)-like protein on the basis of its amino terminal sequence homology. We purified the protein further from the same materials by gel filtration and reversed-phase column chromatographies with RNase activity as an index. The purified protein was designated RNase UpI-2. The catalytic activity and its sensitivity to inhibition by divalent cations suggest that the protein is related to nonsecretory RNase. The estimated molecular weight of RNase UpI-2 (38 kDa) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis was significantly higher than that of urinary nonsecretory RNases (13 to 19 kDa) reported so far. After trifluoromethanesulfonic acid treatment, the molecular weight of RNase UpI-2 was reduced and approached that of nonsecretory RNase, which indicated that the protein contains a significant amount of carbohydrate (approximately 50%). RNase UpI-2 was immunoreactive with antibodies to a nonsecretory RNase, RNAase 1 [Yasuda et al. (1988) Biochim. Biophys. Acta 965, 185-194]. By immunoblot analysis of the protein freshly prepared from various urine samples, it was shown that a considerable amount of RNase UpI-2 is present in urine of pregnant women, but only a trace of RNase UpI-2, if any, was detected in urine of nonpregnant women and men. These results suggest the possibility that RNase UpI-2 may have been formed via a specific protein modification in pregnant women.
Sakakibara
R
R
Department of Biochemistry, School of Clinical Pharmaceutical Sciences, Nagasaki University.
Hashida
K
K
Kitahara
T
T
Ishiguro
M
M
D000595:Amino Acid Sequence; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D011247:Pregnancy / Q000652:urine*; D012260:Ribonucleases / Q000302:isolation & purification / Q000652:urine*
D012260:Ribonucleases