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Studies on the solubilized porcine ileal intrinsic factor receptor and on a 340 000-dalton component binding vitamin B-12.
Biochim Biophys Acta. 1977 Oct 25; 499(3):373-81.BB

Abstract

A 340 000-dalton component "C-III" was found when Triton X-100-containing extracts of ileal mucosa were incubated with human or porcine intrinsic factor vitamin B-12 preparations. It was not formed when abnormal human intrinsic factor, unable to attach to the intrinsic factor receptor, was used. Prolonged storage promoted the trnasfer of vitamin B-12 to it from the vitamin B-12-intrinsic factor recptor species C-I and C-II. The component was also present in ileal extracts prepared with or without detergent and it bound vitamin B-12 directly. Immunologically and by electrofocusing it could be classified as a cobalophilin but its molecular dimensions were larger than described for cobalophilin. It thus represents a novel vitamin B-12 binding protein, possibly a macromolecular acceptor of vitamin B-12 which accepts vitamin B-12 bound via intrinsic factor to the ileal intrinsic factor recptor. In the presence of EDTA or at low pH, vitamin B-12-intrinsic factor did not bind to any of the receptor species and under the same conditions it could all be dissociated from the receptor complexes but not from C-III. The dissociated receptor was able to recombine with vitamin B-12-intrinsic factor and it appeared to bind free and vitamin B-12-bound intrinsic factor in vivo.

Authors

No affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

911890

Citation

Marcoullis, G. "Studies On the Solubilized Porcine Ileal Intrinsic Factor Receptor and On a 340 000-dalton Component Binding Vitamin B-12." Biochimica Et Biophysica Acta, vol. 499, no. 3, 1977, pp. 373-81.
Marcoullis G. Studies on the solubilized porcine ileal intrinsic factor receptor and on a 340 000-dalton component binding vitamin B-12. Biochim Biophys Acta. 1977;499(3):373-81.
Marcoullis, G. (1977). Studies on the solubilized porcine ileal intrinsic factor receptor and on a 340 000-dalton component binding vitamin B-12. Biochimica Et Biophysica Acta, 499(3), 373-81.
Marcoullis G. Studies On the Solubilized Porcine Ileal Intrinsic Factor Receptor and On a 340 000-dalton Component Binding Vitamin B-12. Biochim Biophys Acta. 1977 Oct 25;499(3):373-81. PubMed PMID: 911890.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Studies on the solubilized porcine ileal intrinsic factor receptor and on a 340 000-dalton component binding vitamin B-12. A1 - Marcoullis,G, PY - 1977/10/25/pubmed PY - 1977/10/25/medline PY - 1977/10/25/entrez SP - 373 EP - 81 JF - Biochimica et biophysica acta JO - Biochim Biophys Acta VL - 499 IS - 3 N2 - A 340 000-dalton component "C-III" was found when Triton X-100-containing extracts of ileal mucosa were incubated with human or porcine intrinsic factor vitamin B-12 preparations. It was not formed when abnormal human intrinsic factor, unable to attach to the intrinsic factor receptor, was used. Prolonged storage promoted the trnasfer of vitamin B-12 to it from the vitamin B-12-intrinsic factor recptor species C-I and C-II. The component was also present in ileal extracts prepared with or without detergent and it bound vitamin B-12 directly. Immunologically and by electrofocusing it could be classified as a cobalophilin but its molecular dimensions were larger than described for cobalophilin. It thus represents a novel vitamin B-12 binding protein, possibly a macromolecular acceptor of vitamin B-12 which accepts vitamin B-12 bound via intrinsic factor to the ileal intrinsic factor recptor. In the presence of EDTA or at low pH, vitamin B-12-intrinsic factor did not bind to any of the receptor species and under the same conditions it could all be dissociated from the receptor complexes but not from C-III. The dissociated receptor was able to recombine with vitamin B-12-intrinsic factor and it appeared to bind free and vitamin B-12-bound intrinsic factor in vivo. SN - 0006-3002 UR - https://www.unboundmedicine.com/medline/citation/911890/Studies_on_the_solubilized_porcine_ileal_intrinsic_factor_receptor_and_on_a_340_000_dalton_component_binding_vitamin_B_12_ L2 - https://linkinghub.elsevier.com/retrieve/pii/0304-4165(77)90068-X DB - PRIME DP - Unbound Medicine ER -