Document Detail


Vitamin A transport in plasma of the non-mammalian vertebrates: isolation and partial characterization of piscine retinol-binding protein.
MedLine Citation:
PMID:  562910     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Studies were conducted to explore vitamin A transport in the non-mammalian vertebrates, especially Pisces, Amphibia, and Reptilia, and to isolate and partially characterize piscine retinol-binding protein. Retinol-containing proteins in fresh plasma obtained from bullfrogs and a turtle exhibited similar properties to those found in mammalian and chicken plasma: i.e., molecular weight of about 60,000-80,000 as estimated by gel filtration and binding affinity to prealbumin on human prealbumin-Sepharose affinity chromatography. In sharp contrast, vitamin A-containing proteins in plasma from larvae of bullfrogs as well as three fishes (carp, blue sharks, and young yellowtails) appeared to be present in plasma as monomeric retinol-binding proteins without any affinity to human prealbumin. On the other hand, plasma vitamin A in the lamprey (Cyclostomes) was found to exist exclusively as an ester form in association with the lipoproteins of hydrated density less than 1.21 g/ml. Piscine retinol-binding protein was isolated from pooled plasma of young yellowtails and was converted (1000-fold purification) to a homogeneous component by a procedural sequence that included gel filtration on Sephadex G-100, chromatography on SP-Sephadex, gel isoelectric focusing, and, finally, polyacrylamide gel electrophoresis. Purified piscine retinol-binding protein showed physico-chemical properties distinctly different from the mammalian and chicken retinol-binding proteins examined, i.e., a smaller molecular weight of approximately 16,000, a lower isoelectric point of 4.3, a prealbumin mobility on analytical polyacrylamide gel electrophoresis, and a lack of binding affinity for human prealbumin; however, it displayed similar characteristics in two ways: a 1:1 molar complex with retinol, and a high content of tryptophan (four residues). These results strongly suggest that the piscine retinol-binding protein is a prototype of the specific vitamin A-transporting protein in plasma of the vertebrates, being modified later in evolution, during phylogenetic development of the vertebrates, to acquire a binding site for prealbumin on the molecule.
Authors:
Y Shidoji; Y Muto
Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  Journal of lipid research     Volume:  18     ISSN:  0022-2275     ISO Abbreviation:  J. Lipid Res.     Publication Date:  1977 Nov 
Date Detail:
Created Date:  1978-01-27     Completed Date:  1978-01-27     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0376606     Medline TA:  J Lipid Res     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  679-91     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Amino Acids / analysis
Animals
Anura
Fishes
Humans
Male
Molecular Weight
Prealbumin
Protein Binding
Rabbits
Rats
Retinol-Binding Proteins / isolation & purification,  metabolism*
Retinol-Binding Proteins, Plasma
Turtles
Vitamin A / blood*,  metabolism
Chemical
Reg. No./Substance:
0/Amino Acids; 0/Prealbumin; 0/Retinol-Binding Proteins; 0/Retinol-Binding Proteins, Plasma; 11103-57-4/Vitamin A

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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