Identification of pregnancy-associated glycoproteins by peptide mass fingerprinting in water buffalo (Bubalus bubalis).

Ruminant placentas synthesize pregnancy-associated glycoproteins (PAGs) during pregnancy, which serve as biomarkers of pregnancy. The present study was conducted to verify, whether PAGs are expressed in buffalo placenta by using lectin-based affinity chromatography and peptide mass finger printing (PMF). Fetal cotyledonary tissues were collected from gravid uteri procured from slaughtered house. Proteins were extracted and subjected to wheat germ agglutinin (WGA) lectin affinity chromatography to isolate the PAGs. The isolated glycoproteins were separated by one-dimensional SDS-PAGE. PMF results of the 75 kDa protein revealed presence of two PAGs (PAG-7 and -11). The PAG-7 consisted of about 170 mass signals, of which 16 were assigned to corresponding/translated cDNA sequences of buffalo PAG-7, leading to sequence coverage of 40%. PMF result of PAG-11 showed 170 mass signals, of which 15 were assigned to buffalo PAG-11, leading to sequence coverage of 34%. In conclusion, the glycoprotein isolated from placental extract corresponding to 75 kDa band on SDS PAGE gel was a mixture of PAG-7 and -11, which may help in development of suitable diagnostics for pregnancy in buffalo.