Carbohydrate-binding profile of a pregnancy-associated rat uterine glycoprotein.
Sugar-binding proteins obtained from the peri-implantation uterine tissue have been thought in recent years to have significant roles in embryo implantation, where carbohydrate moieties of the protein are actively involved. Based on this rationale a mannose-containing glycoprotein/lectin (named uterine agglutinin or UA) was purified by Concanavalin A (Con A) affinity chromatography in a previous study. A modification of the original purification procedure to include a 33% ammonium sulfate fractionation improves the yield of the protein significantly. An alternative purification procedure by Mannan affinity matrix, indicates that apart from containing mannose, UA possesses mannose-binding properties as well. In this paper, we report some of the biochemical and more specifically, the carbohydrate-binding characteristics of UA. The protein is seen to contain mannose-6-phosphate (M-6-P)-binding sites, which is of importance since M-6-P receptors have a large number of biologically significant roles, including that of binding to growth factors. SDS-PAGE, gel filtration chromatography and alkaline PAGE indicate the homogenous nature of the protein with subunit molecular weights of 36 kDa and 19 kDa, and a native size of 64 kDa. Amino acid analysis shows glycine, glutamic acid and aspartic acid to be the major constituents. UA is a glycoprotein and shows presence of N-acetyl glucosamine and galactose, apart from mannose. De nove synthesis studies in the presence of tunicamycin show that the carbohydrate moiety of the glycoprotein is attached by N-linkage to the protein. Binding characteristics of the protein is studied quantitatively in which (125I)-labelled lectin is bound to Mannan-Sepharose affinity matrix.(ABSTRACT TRUNCATED AT 250 WORDS)
Indian Institute of Chemical Biology, Jadavpur, Calcutta.
M
M
Das
P K
PK
Mukhopadhyay
M
M
Chowdhury
D000117:Acetylglucosamine / Q000032:analysis; D000373:Agglutinins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001665:Binding Sites; D002241:Carbohydrates; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D003208:Concanavalin A; D004591:Electrophoresis, Polyacrylamide Gel; D010064:Embryo Implantation; D005260:Female; D005690:Galactose / Q000032:analysis; D006023:Glycoproteins; D007700:Kinetics; D008358:Mannose / Q000032:analysis; D011257:Pregnancy Proteins / Q000737:chemistry* / Q000302:isolation & purification; D051381:Rats; D017207:Rats, Sprague-Dawley; D014599:Uterus / Q000737:chemistry* / Q000378:metabolism
D000373:Agglutinins; D000596:Amino Acids; D002241:Carbohydrates; D006023:Glycoproteins; D011257:Pregnancy Proteins; C057612:sialic acid specific agglutinin protein, rat; D003208:Concanavalin A; D008358:Mannose; D000117:Acetylglucosamine; D005690:Galactose