Exclusive Expression of Transketolase in the Vanadocytes of the Vanadium-Rich Ascidian, Ascidia sydneiensis samea
Use this link to cite this item : https://ir.lib.hiroshima-u.ac.jp/00000023
ID | 23 |
file | |
creator |
Uyama, Taro
Kanamori, Kan
Michibata, Hitoshi
|
subject | Chordates
Metal Accumulation
Redox
Gene Expression
|
NDC |
Biology
|
abstract | Ascidians, especially those belonging to the Ascidiidae, are known to accumulate extremely high levels of vanadium in vanadocytes, one type of blood (coelomic) cell. Vanadium, which exists in the +5 oxidation state in seawater, is accumulated in the vanadocytes and reduced to the +3 oxidation state. We have been trying to characterize all of the polypeptides specific to vanadocytes and to specify the proteins that participate in the accumulation and reduction of vanadium. To date, we have localized three enzymes in vanadocytes: 6-phosphogluconate dehydrogenase (6-PGDH: EC 1.1.1.44), glucose-6-phosphate dehydrogenase (G6PDH: EC 1.1.1.49), and glycogen phosphorylase (GP: EC 2.4.1.1), all of which are involved in the pentose phosphate pathway. In the current study, we cloned a cDNA for transketolase, an essential and rate-limiting enzyme in the non-oxidative part of the pentose phosphate pathway, from vanadocytes. The cDNA encoded a protein of 624 amino acids, which showed 61.8 0dentity to the human adult-type transketolase gene product. By immunocytochemistry and immunoblot analyses, the transketolase was revealed to be a protein that was expressed only in vanadocytes and not in any of the more than ten other types of blood cell. This finding, taken together with the localized expression of the other three enzymes, strongly supports the hypothesis that the pentose phosphate pathway functions exclusively in vanadocytes.
|
journal title |
Biochimica et biophysica acta
|
volume | Volume 1494
|
start page | 83
|
end page | 90
|
date of issued | 2000
|
publisher | Elsevier Science B.V.
|
issn | 0167-4781
|
ncid | |
publisher doi | |
pubmed id | |
language |
eng
|
nii type |
Journal Article
|
HU type |
Journal Articles
|
DCMI type | text
|
format | application/pdf
|
text version | author
|
rights | Copyright (c) 2000 Elsevier Science B.V.
|
relation is version of URL | http://dx.doi.org/10.1016/S0167-4781(00)00222-0
|
department |
Graduate School of Science
|