Biochemical characterization of mouse vitamin D-dependent calcium-binding protein. Evidence for its presence in embryonic life.
We compared immunochemical and biochemical properties of the vitamin D-dependent Ca2+-binding protein (CaBP) from rat and mouse intestine. The two intestinal CaBP species were extensively purified by gel filtration and successive anion-exchange chromatographies. Both had a similar mol.wt. of 9000. Their pI values differed markedly, being 8.0 and 4.9 in rat and mouse CaBP respectively. Accordingly, mouse CaBP displayed more anodal migration in electrophoresis under non-denaturing conditions. Both mouse and rat CaBP only exhibited partial immunochemical similarities, but their amino acid compositions were very similar. Chromatofocusing was also found to be a good method of detecting calcium-dependent changes in their pI. We developed a sensitive radioimmunoassay for mouse CaBP enabling us to detect substantial amounts of CaBP in uterus, yolk sac and chorio-allantoic placenta. During normal mouse gestation, CaBP appeared on day 12 in the chorio-allantoic placenta but was already present on day 9 in the yolk sac, where its level rose sharply between days 9.5 and 10. CaBP may therefore be considered as a new marker for mouse yolk-sac differentiation.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002852:Chromatography, Ion Exchange; D003656:Decidua / Q000378:metabolism; D004386:Duodenum / Q000378:metabolism; D005260:Female; D007413:Intestinal Mucosa / Q000378:metabolism; D051379:Mice; D008970:Molecular Weight; D010920:Placenta / Q000378:metabolism; D011247:Pregnancy; D011863:Radioimmunoassay; D051381:Rats; D064030:S100 Calcium Binding Protein G / Q000276:immunology / Q000378:metabolism*; D015017:Yolk Sac / Q000378:metabolism
D000596:Amino Acids; D002135:Calcium-Binding Proteins; D064030:S100 Calcium Binding Protein G