TY - JOUR
T1 - Dog intestinal mucosa contains two vitamin D-stimulated calcium binding proteins
AU - Alpers, David H.
AU - Grimme, Nancy
AU - Smith, Richard
AU - Avioli, Louis V.
PY - 1980
Y1 - 1980
N2 - Dog intestinal mucosa has been found to contain more than one vitamin D-responsive calcium-binding protein (CaBP). Duodenal and upper jejunal mucosa contains a protein that has a mol wt of 19,000 and a Kd of 1.2 μM, and that increases in activity over twofold after administration of 1,25 (OH)2 vitamin D3. This protein could not be demonstrated in ileal tissue. In ileal mucosa all the calcium binding activity resides in fractions that elute from Sephadex G200 with a mol wt of about 57,000. Calcium-binding activity was demonstrated in gel electrophoresis corresponding to a protein with an Rf of about 0.5, unlike the small CaBP, which has an Rf of 1.0. The calcium-binding activity from the ileum was demonstrated to coincide with a protein band on acrylamide gel electrophoresis, and to be destroyed by pronase. This large CaBP responded to 1,25 (OH)2 vitamin D3 by increasing activity by about 50%, and was inhibited similarly to the small protein by Sr, Ba, and Mg. Neither fresh tissue homogenates, nor explants cultured up to 20 hr showed any evidence of the small CaBP on disc gel acrylamide electrophoresis. The small CaBP could be demonstrated on gel electrophoresis only in tissue that was partially autolyzed or was treated with a 10% (milligrams per milligram) solution of trypsin. The small CaBP was relatively resistant to trypsin. It is suggested that the small CaBP may be derived at least in part from the large protein.
AB - Dog intestinal mucosa has been found to contain more than one vitamin D-responsive calcium-binding protein (CaBP). Duodenal and upper jejunal mucosa contains a protein that has a mol wt of 19,000 and a Kd of 1.2 μM, and that increases in activity over twofold after administration of 1,25 (OH)2 vitamin D3. This protein could not be demonstrated in ileal tissue. In ileal mucosa all the calcium binding activity resides in fractions that elute from Sephadex G200 with a mol wt of about 57,000. Calcium-binding activity was demonstrated in gel electrophoresis corresponding to a protein with an Rf of about 0.5, unlike the small CaBP, which has an Rf of 1.0. The calcium-binding activity from the ileum was demonstrated to coincide with a protein band on acrylamide gel electrophoresis, and to be destroyed by pronase. This large CaBP responded to 1,25 (OH)2 vitamin D3 by increasing activity by about 50%, and was inhibited similarly to the small protein by Sr, Ba, and Mg. Neither fresh tissue homogenates, nor explants cultured up to 20 hr showed any evidence of the small CaBP on disc gel acrylamide electrophoresis. The small CaBP could be demonstrated on gel electrophoresis only in tissue that was partially autolyzed or was treated with a 10% (milligrams per milligram) solution of trypsin. The small CaBP was relatively resistant to trypsin. It is suggested that the small CaBP may be derived at least in part from the large protein.
UR - http://www.scopus.com/inward/record.url?scp=0018955024&partnerID=8YFLogxK
U2 - 10.1016/0016-5085(80)90138-9
DO - 10.1016/0016-5085(80)90138-9
M3 - Article
C2 - 6249694
AN - SCOPUS:0018955024
SN - 0016-5085
VL - 79
SP - 259
EP - 264
JO - Gastroenterology
JF - Gastroenterology
IS - 2
ER -