ISSN:
1399-3054
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
Three thiamin-binding proteins (TBPs) from sesame (Sesamum indicum L.) seeds (STBP-I, -II and -III) were characterized. Binding of thiamin to the three STBPs was inhibited by pyrithiamin, which did not inhibit the binding of thiamin to TBPs from other plant seeds. STBP-I alone bound 2-northiamin and hydroxyethylthiamin. Isoelectric points (pIs) of STBP-I and -II both were 7.5. The pI of STBP-III was 6.5. STBPs did not have immunological homology with TBPs from rice seeds and buckwheat seeds. On the other hand, the amino acid compositions of the small and large polypeptides isolated from STBP-I, -II and -III resembled each other. Both the polypeptides contained large amounts of Glu (or Gln) and Arg. The small polypeptides contained more Ser than the large polypeptides. The N-terminal amino acid sequences (the first 29 residues) of the small polypeptides were identified. The N-terminal amino acid sequences of the three STBPs were the same. The small polypeptides had homology to castor bean 2S albumin small subunit. These results showed that STBPs were part of a plant protein superfamily and that STBPs differed from the TBPs of other plant seeds as to the binding to thiamin-related compounds and immunological properties, and further, that STBP-I, -II and -III differed in the affinity for thiamin-related compounds and pI, indicating that STBP-I, -II and -III are isomers.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1034/j.1399-3054.1999.100102.x
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