TY - JOUR
T1 - Development of intestinal brush border membrane proteins in the rat
AU - Seetharam, Bellur
AU - Yeh, Kwo Yih
AU - Moog, Florence
AU - Alpers, David H.
N1 - Funding Information:
This work was supported in part by grants AM 07130, AM 14038, and HD 03490 from the National Institutes of Health. We are grateful to Mr. Michael Veith for preparing the electron micrographs, to Mrs. Carol Goodwin for superb technical assistance and to Mrs. Pam Helms for excellent secretarial assistance. This work was presented in part at the meeting o'f the American Society for Biological Chemists, San Francisco, California, June 6, 1976.
PY - 1977/11/1
Y1 - 1977/11/1
N2 - 1. 1. The proteins of the intestinal microvillus membrane have been studied during post-natal development in the rat (days 12-37). 2. 2. In suckling animals (up to age 20 days), the majority of alkaline phosphatase, glucoamylase and lactase activities in the distal half of the intestine were located in the supernatant fraction (100 000 × g, 60 min). These enzymes were attached to the membrane from the proximal intestine at all ages. 3. 3. Alkaline phosphatase, maltase and lactase activities in the supernatant fractions chromatographed in Sephadex G-200 in positions similar to the corresponding membrane enzyme. Corresponding activities for lysosomal counterparts of maltase and lactase present in the supernatant fraction chromatographed differently. Moreover, pH optimum of the soluble enzymes was 9.2 for phosphatase and 5.5-6.0 for glycoamylase and lactase. The soluble lactase and alkaline phosphatase were inhibited minimally by p-chloromercuribenzoate, and sodium fluoride respectively. L-Phenylalanine (20 mM) did inhibit the soluble phosphatase by 90%. Thus, the soluble enzymes are not mainly of lysosomal origin, but have characteristics of membrane-bound enzymes. 4. 4. Polyacrylamide gel electrophoresis in sodium dodecyl sulfate revealed 18 protein bands which were present in adult membranes. Two other proteins were unique for membranes of distal intestine in suckling rats. The proteins corresponding to known enzyme activity changed as expected with age (e.g. sucrase, maltase increased, lactase decreased). Most of the other proteins were also altered in amount during development. Thus, the changes in the microvillus membrane during development in the rat are not limited to specific enzymes.
AB - 1. 1. The proteins of the intestinal microvillus membrane have been studied during post-natal development in the rat (days 12-37). 2. 2. In suckling animals (up to age 20 days), the majority of alkaline phosphatase, glucoamylase and lactase activities in the distal half of the intestine were located in the supernatant fraction (100 000 × g, 60 min). These enzymes were attached to the membrane from the proximal intestine at all ages. 3. 3. Alkaline phosphatase, maltase and lactase activities in the supernatant fractions chromatographed in Sephadex G-200 in positions similar to the corresponding membrane enzyme. Corresponding activities for lysosomal counterparts of maltase and lactase present in the supernatant fraction chromatographed differently. Moreover, pH optimum of the soluble enzymes was 9.2 for phosphatase and 5.5-6.0 for glycoamylase and lactase. The soluble lactase and alkaline phosphatase were inhibited minimally by p-chloromercuribenzoate, and sodium fluoride respectively. L-Phenylalanine (20 mM) did inhibit the soluble phosphatase by 90%. Thus, the soluble enzymes are not mainly of lysosomal origin, but have characteristics of membrane-bound enzymes. 4. 4. Polyacrylamide gel electrophoresis in sodium dodecyl sulfate revealed 18 protein bands which were present in adult membranes. Two other proteins were unique for membranes of distal intestine in suckling rats. The proteins corresponding to known enzyme activity changed as expected with age (e.g. sucrase, maltase increased, lactase decreased). Most of the other proteins were also altered in amount during development. Thus, the changes in the microvillus membrane during development in the rat are not limited to specific enzymes.
UR - http://www.scopus.com/inward/record.url?scp=0017651584&partnerID=8YFLogxK
U2 - 10.1016/0005-2736(77)90133-X
DO - 10.1016/0005-2736(77)90133-X
M3 - Article
C2 - 411509
AN - SCOPUS:0017651584
SN - 0005-2736
VL - 470
SP - 424
EP - 436
JO - BBA - Biomembranes
JF - BBA - Biomembranes
IS - 3
ER -