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Vitamin B12-binding proteins of r-type, cobalophilin.
Scand J Haematol. 1975 Apr; 14(2):91-107.SJ

Abstract

A gradient was developed for isoelectric focusing in the pH range 2-5. Cobalophilin (earlier called R proteins or vitamin B12-binding proteins of R-type) was isolated from saliva and amniotic fluid in homogeneous form. It was found to be a glycoprotein with a molecular weight of 59,300-69,100. The preparation from amniotic fluid contained 33% carbohydrate. Cobalophilin variants in plasma, serum, granulocytes, platelets, amniotic fluid, milk, saliva and gastric juice were characterized by isoelectric focusing. Most fluids and cells contained the same isoproteins, with pI values between 2.3 and 5.0. Isoproteins of presumably myelogenic origin (e.g. those in granulocytes and plasma) had pI values below 4.2, whereas those of glandular origin (in milk and saliva) had a pI range of 4.0-5.0. Serum contained more cobalophilin than plasma, owing to release of this protein from granulocytes during clotting. This phenomenon also changed the isoprotein pattern. Plasma and serum from newborn infants and from patients with leucocytosis, polycythaemia vera and chronic myelogenous leukaemia contained the same isoproteins as were found in plasma from healthy subjects. In addition to these, isoproteins with lower than 'normal' pI values were often found in chronic myelogenous leukaemia and occasionally in leucocytosis. It is concluded that cobalophilin from different fluids and cells is a single microheterogeneous protein with a variable carbohydrate composition. The distribution of cobalophilin in different body fluids and cells supports the suggestion that cobalophilin is an antimicrobial protein (Gullberg 1972) like lactoferrin and lysozyme.

Authors

No affiliation info available

Pub Type(s)

Comparative Study
Journal Article

Language

eng

PubMed ID

1056622

Citation

Stenman, U H.. "Vitamin B12-binding Proteins of R-type, Cobalophilin." Scandinavian Journal of Haematology, vol. 14, no. 2, 1975, pp. 91-107.
Stenman UH. Vitamin B12-binding proteins of r-type, cobalophilin. Scand J Haematol. 1975;14(2):91-107.
Stenman, U. H. (1975). Vitamin B12-binding proteins of r-type, cobalophilin. Scandinavian Journal of Haematology, 14(2), 91-107.
Stenman UH. Vitamin B12-binding Proteins of R-type, Cobalophilin. Scand J Haematol. 1975;14(2):91-107. PubMed PMID: 1056622.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Vitamin B12-binding proteins of r-type, cobalophilin. A1 - Stenman,U H, PY - 1975/4/1/pubmed PY - 1975/4/1/medline PY - 1975/4/1/entrez SP - 91 EP - 107 JF - Scandinavian journal of haematology JO - Scand J Haematol VL - 14 IS - 2 N2 - A gradient was developed for isoelectric focusing in the pH range 2-5. Cobalophilin (earlier called R proteins or vitamin B12-binding proteins of R-type) was isolated from saliva and amniotic fluid in homogeneous form. It was found to be a glycoprotein with a molecular weight of 59,300-69,100. The preparation from amniotic fluid contained 33% carbohydrate. Cobalophilin variants in plasma, serum, granulocytes, platelets, amniotic fluid, milk, saliva and gastric juice were characterized by isoelectric focusing. Most fluids and cells contained the same isoproteins, with pI values between 2.3 and 5.0. Isoproteins of presumably myelogenic origin (e.g. those in granulocytes and plasma) had pI values below 4.2, whereas those of glandular origin (in milk and saliva) had a pI range of 4.0-5.0. Serum contained more cobalophilin than plasma, owing to release of this protein from granulocytes during clotting. This phenomenon also changed the isoprotein pattern. Plasma and serum from newborn infants and from patients with leucocytosis, polycythaemia vera and chronic myelogenous leukaemia contained the same isoproteins as were found in plasma from healthy subjects. In addition to these, isoproteins with lower than 'normal' pI values were often found in chronic myelogenous leukaemia and occasionally in leucocytosis. It is concluded that cobalophilin from different fluids and cells is a single microheterogeneous protein with a variable carbohydrate composition. The distribution of cobalophilin in different body fluids and cells supports the suggestion that cobalophilin is an antimicrobial protein (Gullberg 1972) like lactoferrin and lysozyme. SN - 0036-553X UR - https://www.unboundmedicine.com/medline/citation/1056622/Vitamin_B12_binding_proteins_of_r_type_cobalophilin_ L2 - https://antibodies.cancer.gov/detail/CPTC-GSTP1-1 DB - PRIME DP - Unbound Medicine ER -