174:
and bind these groups tightly. Vanabins on the other hand have a moderate dissociation constant and do not tightly bind vanadium. Most importantly, because of this moderate dissociation constant, vanadium is usually found free-floating and separated from any proteins inside the vacuoles. This is
159:(vanadium-containing blood cells). The vacuoles are kept at a very acidic pH of 1.9 (due to sulfuric acid in it), made possible by pumping hydrogen ions into the vacuoles by use of energy intensive H-ATPase. All the use of NADPH and
20:
190:
The use of vanabins and vanadium for oxygen transport in ascidians and tunicates is doubtful. Another hypothesized reason for these organisms collecting vanadium is to make themselves toxic to
79:, and vanabin proteins have been involved in collecting and accumulating this metal ion. At present there is no conclusive understanding of why these organisms collect vanadium.
427:
Michibata H, Uyama T, Ueki T, Kanamori K (2002). Vanadocytes, cells hold the key to resolving the highly selective accumulation and reduction of vanadium in ascidians.
334:
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The most convincing evidence against vanadium in use for oxygen transport is that many ascidians and tunicates also have
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to collect and maintain the vanadium is extremely energy intensive, unusual for oxygen transporting proteins.
476:
Characterization of
Vanabins, Vanadium-Binding Proteins, Key Substances of Vanadium Accumulation in Ascidians
401:[Studies on the blood of sea squirts. I. Communication. The vanadium compound of the blood cells].
104:
Because of the high concentration of vanadium in the blood, it has been assumed that vanabins are used for
160:
298:
Ciereszko, L.; Ciereszko, E; Harris, E; Lane, C (1962). "On the
Occurrence of Vanadium in Holothurians".
25:
167:
91:. However, later research has found little or no vanadium in this and four other sea cucumber genera.
443:"Untersuchungen über das Blut der Ascidien. I. Mitteilung. Die Vanadiumverbindung der Blutkörperchen"
399:"Untersuchungen über das Blut der Ascidien. 1. Mitteilung. Die Vanadiumverbindung der Blutkörperchen"
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Vanabins accumulate vanadium in the blood cells and produce V(III) species and
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Ueki, Tatsuya; Uwagaki, Masayuki; Yamamoto, Sohei; Michibata, Hitoshi (2014).
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155:. Vanabins also transport the reduced vanadium species into the vacuoles of
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241:"Participation of thioredoxin in the V(V)-reduction reaction by Vanabin2"
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75:. These organisms are able to concentrate vanadium from the surrounding
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140:. This concentration is 10,000,000 times higher than that in seawater.
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Vanadium has been reported in high concentrations in the blood of the
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in their blood that could be assumed to handle all oxygen transport.
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398:
71:. The vanabins extracted from tunicate vanadocytes are often called
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18:
116:. Unfortunately no scientific evidence can be found to back this
19:
333:
Tatsuya Ueki; Nobuo
Yamaguchi & Hitoshi Michibata (2003).
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completely different from other oxygen transporting proteins.
335:"Chloride channel in vanadocytes of a vanadium-rich ascidian
147:
ions (V(IV)) from orthovanadate ions (V(V)), with the use of
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The highest concentration of vanadium found so far, 350
248:
Biochimica et
Biophysica Acta (BBA) - General Subjects
23:
3-D representation of the structure of
Vanabin2 from
447:
166:Other oxygen transporting proteins have a very low
284:A Possible Source of Vanadium in Sedimentary Rocks
55:. Vanabins are found almost exclusively in the
8:
346:Comparative Biochemistry and Physiology
300:Comparative Biochemistry and Physiology
231:
486:Transferring vanabin genes to bacteria
7:
287:. Princeton University. p. 473.
16:Family of vanadium-binding proteins
431:Volume 56 Issue 6, Pages 421 - 434
429:Microscopy Research and Technique.
127:, was found in the blood cells of
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482: (archived December 18, 2005)
1:
459:10.1515/bchm2.1911.72.5-6.494
415:10.1515/bchm2.1911.72.5-6.494
358:10.1016/s1096-4959(03)00175-1
67:(sea squirts), including the
312:10.1016/0010-406X(62)90034-8
281:Phillips, Alexander (1918).
260:10.1016/j.bbagen.2014.07.023
179:Vanabins not oxygen carriers
41:vanadium-associated proteins
100:Vanabins as oxygen carriers
527:
337:Ascidia sydneiensis samea
33:
168:dissociation constant
22:
403:Biological Chemistry
26:Ascisia sydneiensis
506:Vanadium compounds
441:Henze, M. (1911).
45:vanadium chromagen
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254:(11): 3238–3245.
170:with their metal
133:belonging to the
95:Possible function
47:) are a group of
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453:(5–6): 494–501.
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409:(5–6): 494–501.
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368:. Archived from
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172:prosthetic group
112:or copper-based
108:like iron-based
106:oxygen transport
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501:Metalloproteins
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480:Wayback Machine
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210:German chemist
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130:Ascidia gemmata
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53:metalloproteins
39:(also known as
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375:on 6 June 2014
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200:microorganisms
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153:reducing agent
138:Phlebobranchia
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377:. Retrieved
370:the original
352:(1): 91–98.
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220:ascidiaceans
212:Martin Henze
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84:sea cucumber
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73:hemovanadins
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214:discovered
157:vanadocytes
61:vanadocytes
57:blood cells
511:Ascidiacea
495:Categories
226:References
185:hemocyanin
118:hypothesis
114:hemocyanin
110:hemoglobin
69:Ascidiacea
63:, of some
379:13 August
222:in 1911.
196:parasites
192:predators
88:Stichopus
65:tunicates
51:-binding
397:(1911).
366:12941642
320:14021342
268:25108063
216:vanadium
135:suborder
77:seawater
49:vanadium
37:Vanabins
478:at the
395:Henze M
206:History
145:vanadyl
364:
318:
266:
373:(PDF)
342:(PDF)
244:(PDF)
151:as a
149:NADPH
59:, or
31:samea
29:var.
381:2013
362:PMID
316:PMID
264:PMID
252:1840
198:and
455:doi
411:doi
354:doi
350:136
308:doi
256:doi
218:in
161:ATP
43:or
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451:72
449:.
445:.
407:72
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348:.
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314:.
302:.
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250:.
246:.
202:.
194:,
125:mM
120:.
461:.
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383:.
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339:"
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304:7
270:.
258::
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
