title: Immunoglobulins associated with elevated riboflavin binding by plasma from cancer patients.
abstract: Plasma from 182 patients with different malignant diseases was tested for riboflavin binding by immunoglobulins, which have been recently identified as major carriers of this micronutrient. A wide range of binding (5.9 to 130 pmole/ml plasma) was observed, and significant elevations were found for patients having breast cancer (21.2 +/- 1.9, P less than 0.05) and melanoma (25.7 +/- 1.9, P less than 0.001) compared to controls (15.5 +/- 1.9). The proteins responsible for a majority of the higher binding were identified as immunoglobulins, based on their elution from gel filtration columns and the removal of 57-88% of the non-albumin binding by treating of plasma with Protein A-agarose. The binding was only weakly related to the total concentration of immunoglobulins (r = 0.11 by linear regression analysis), however, and is apparently due to a subclass that is elevated in some types of cancer. Elevated levels of these immunoglobulins may contribute to the lower urinary levels and clearance of riboflavin in cancer.
mesh_terms: D001943:Breast Neoplasms / Q000097:blood; D002850:Chromatography, Gel; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D008545:Melanoma / Q000097:blood; D009369:Neoplasms / Q000097:blood* / Q000378:metabolism; D009391:Nephelometry and Turbidimetry; D011485:Protein Binding; D012256:Riboflavin / Q000097:blood / Q000378:metabolism*; D012685:Sepharose
chemical_list: D007074:Immunoglobulin G; D012685:Sepharose; D012256:Riboflavin