The Carriers of Native Vitamin B12 in Normal Human Serum

1977 ◽  
Vol 53 (5) ◽  
pp. 453-457 ◽  
Author(s):  
C. A. Hall
Keyword(s):  
Vitamin B12 ◽  
Human Serum ◽  
Isotope Dilution ◽  
Serum Vitamin ◽  
Total Serum ◽  
Plasma Vitamin ◽  
Isotope Dilution Assay ◽  
Dilution Assay ◽  
Normal Human ◽  
Transcobalamin Ii

1. After fractionation of the vitamin B12-binding proteins of ten normal sera the components containing transcobalamin II and R-type binders of vitamin B12 respectively were studied for endogenous vitamin B12 content by two distinct systems of vitamin B12 assay. 2. The measurements of total serum vitamin B12 by either bioassay with Euglena gracilis or a radioisotope dilution assay agreed closely. 3. The native vitamin B12 carried by transcobalamin II was higher as measured by bioassay than by isotope dilution assay. 4. The presence of the transcobalamin II fraction of human serum altered the key reaction between the binding reagent of the isotope dilution assay, so that this assay failed to measure vitamin B12 quantitatively. 5. Probably, the mean fraction of plasma vitamin B12 carried by transcobalamin II is in the range 20–30%.

The Transport of Endogenous Vitamin B12 in Normal Human Serum

1976 ◽  
Vol 51 (1) ◽  
pp. 47-52
Author(s):  
J. M. England ◽  
Margaret C. Down ◽  
Irene J. Wise ◽  
J. C. Linnell
Keyword(s):  
Vitamin B12 ◽  
Human Serum ◽  
Normal Subjects ◽  
Normal Human Serum ◽  
Normal Human ◽  
Transcobalamin I ◽  
Transcobalamin Ii

1. Serum from normal subjects has been chromatographed on Sephadex G-200 columns and the fractions containing transcobalamins 0, I and II have been identified. 2. The fractions corresponding to transcobalamin I contained, on average, 90% of the endogenous vitamin B12. Only 3% was attached to transcobalamin 0, and 7% was bound to transcobalamin II.

Quantitation of Rotundone in Grapefruit (Citrus paradisi) Peel and Juice by Stable Isotope Dilution Assay

2017 ◽  
Vol 65 (24) ◽  
pp. 5026-5033 ◽  
Author(s):  
Akira Nakanishi ◽  
Yusuke Fukushima ◽  
Norio Miyazawa ◽  
Keisuke Yoshikawa ◽  
Tomoko Maeda ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Isotope Dilution ◽  
Stable Isotope Dilution Assay ◽  
Citrus Paradisi ◽  
Stable Isotope Dilution ◽  
Isotope Dilution Assay ◽  
Dilution Assay

scholarly journals Quantitative Analysis of 2-Aminoacetophenone in Off-Flavored Wines by Stable Isotope Dilution Assay

1996 ◽  
Vol 79 (2) ◽  
pp. 583-586 ◽  
Author(s):  
Bettina Dollmann ◽  
Dominicus Wichmann ◽  
Alfred Schmitt ◽  
Hans Koehler ◽  
Peter Schreier
Keyword(s):  
Quantitative Analysis ◽  
Stable Isotope ◽  
Isotope Dilution ◽  
Internal Standard ◽  
Stable Isotope Dilution Assay ◽  
Isotope Dilution Analysis ◽  
Model Experiments ◽  
Stable Isotope Dilution ◽  
Isotope Dilution Assay ◽  
Dilution Assay

Abstract Isotope dilution analysis was used to quantitate 2- aminoacetophenone in wines exhibiting the so- called untypical aging off-flavor. d3-Aminoacetophe- none was synthesized and used as isotopomeric internal standard. The method of quantitation was verified by several model experiments. In the off-flavored wines studied, amounts of 2-aminoacetophe none ranging from 0.7 to 12.8 μg/L were determined.

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