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Published on: August 9, 2019
A single rainbow trout cobalamin-binding protein stands in for three human binders
Eva Greibe1, Sergey Fedosov, Boe S Sorensen
1Department of Clinical Biochemistry, Aarhus University Hospital, 8000 Aarhus, Denmark. evagreibe@gmail.com
The Journal of Biological Chemistry
|August 9, 2012
Summary
Researchers identified a single cobalamin-binding protein in rainbow trout. This protein shares characteristics with human haptocorrin, intrinsic factor, and transcobalamin, acting as an intermediate form.
Area of Science:
- Comparative biochemistry
- Zoology
- Molecular biology
Background:
- Mammalian cobalamin (vitamin B12) transport involves haptocorrin, intrinsic factor, and transcobalamin.
- The specific cobalamin-binding proteins in lower vertebrates are not well understood.
Purpose of the Study:
- To characterize cobalamin-binding proteins in rainbow trout (Oncorhynchus mykiss).
- To compare these proteins with their human counterparts.
Main Methods:
- Assessed cobalamin-binding capacity in various trout tissues and fluids.
- Purified and sequenced the trout cobalamin-binding protein.
- Analyzed protein stability, binding affinity, and immunological properties.
- Compared conserved residues in the cobalamin-binding site.
Main Results:
- High cobalamin-binding capacity was observed in trout stomach, roe, roe fluid, and plasma.
- A single soluble cobalamin-binding protein was identified across these samples.
- The trout protein exhibited properties intermediate between human haptocorrin, intrinsic factor, and transcobalamin.
- It was glycosylated and showed spectral similarities to human binding proteins.
Conclusions:
- Rainbow trout possess a single soluble cobalamin-binding protein.
- This protein structurally and functionally resembles an intermediate form of the three human cobalamin-binding proteins.
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