Transport of inorganic phosphate and C3- and C6-sugar phosphates across the envelope membranes of potato tuber amyloplasts

By means of the infusion of small amounts of sodium sulphate it has been possible to elevate the filtered load of inorganic phosphate to the renal tubule in fasted dogs without the administration of exogenous phosphate. Under these circumstances, the reabsorption of phosphate remains virtually complete, even when filtered loads are reached which result in a substantial phosphaturia when phosphate has been administered. By comparing phosphate reabsorption and excretion in fasted animals, and in animals at various intervals after feeding, the existence of homeostatic adjustments in the renal tubular transport of inorganic phosphate has been demonstrated. The available evidence suggests that the intracellular disposition of phosphate itself may be an important factor in determining the rate of renal tubular phosphate transport at filtered loads in the physiological range. The limitations of the determination of the phosphate "Tm" as a device for studying homeostatic processes have been discussed.

Download Full-text

HOMEOSTATIC ADJUSTMENT IN THE RENAL TUBULAR TRANSPORT OF INORGANIC PHOSPHATE IN THE DOG

Canadian Journal of Biochemistry and Physiology ◽

10.1139/o55-079 ◽

1955 ◽

Vol 33 (4) ◽

pp. 638-650 ◽

Cited By ~ 6

Author(s):

James G. Foulks

Keyword(s):

Inorganic Phosphate ◽

Renal Tubule ◽

Phosphate Transport ◽

Sodium Sulphate ◽

Tubular Transport ◽

Renal Tubular Transport ◽

Transport Of Inorganic Phosphate ◽

Renal Tubular ◽

Filtered Load

By means of the infusion of small amounts of sodium sulphate it has been possible to elevate the filtered load of inorganic phosphate to the renal tubule in fasted dogs without the administration of exogenous phosphate. Under these circumstances, the reabsorption of phosphate remains virtually complete, even when filtered loads are reached which result in a substantial phosphaturia when phosphate has been administered. By comparing phosphate reabsorption and excretion in fasted animals, and in animals at various intervals after feeding, the existence of homeostatic adjustments in the renal tubular transport of inorganic phosphate has been demonstrated. The available evidence suggests that the intracellular disposition of phosphate itself may be an important factor in determining the rate of renal tubular phosphate transport at filtered loads in the physiological range. The limitations of the determination of the phosphate "Tm" as a device for studying homeostatic processes have been discussed.

Download Full-text

Incorporation of Inorganic Phosphate into Sugar Phosphates during Carbon Dioxide Fixation by Illuminated Chloroplasts

Nature ◽

10.1038/210793a0 ◽

1966 ◽

Vol 210 (5038) ◽

pp. 793-796 ◽

Cited By ~ 15

Author(s):

C. W. BALDRY ◽

C. BUCKE ◽

D. A. WALKER

Keyword(s):

Carbon Dioxide ◽

Inorganic Phosphate ◽

Carbon Dioxide Fixation ◽

Sugar Phosphates

Download Full-text

Specific transport of inorganic phosphate, glucose 6-phosphate, dihydroxyacetone phosphate and 3-phosphoglycerate into amyloplasts from pea roots

FEBS Letters ◽

10.1016/0014-5793(89)80955-x ◽

1989 ◽

Vol 253 (1-2) ◽

pp. 183-186 ◽

Cited By ~ 53

Author(s):

S. Borchert ◽

H. Große ◽

H.W. Heldt

Keyword(s):

Inorganic Phosphate ◽

Dihydroxyacetone Phosphate ◽

Specific Transport ◽

Transport Of Inorganic Phosphate ◽

Pea Roots

Download Full-text

Reconstitution of the hexose phosphate translocator from the envelope membranes of wheat endosperm amyloplasts

Biochemical Journal ◽

10.1042/bj3190717 ◽

1996 ◽

Vol 319 (3) ◽

pp. 717-723 ◽

Cited By ~ 36

Author(s):

Ian J TETLOW ◽

Caroline G BOWSHER ◽

Michael J EMES

Keyword(s):

Inorganic Phosphate ◽

Competitive Inhibitor ◽

Dihydroxyacetone Phosphate ◽

Carrier Protein ◽

Sugar Phosphate ◽

Wheat Endosperm ◽

Single Carrier ◽

Phosphate Translocator ◽

Envelope Membranes ◽

Hexose Phosphates

Amyloplasts were isolated and purified from wheat endosperm and the envelope membranes reconstituted into liposomes. Envelope membranes were solubilized in n-octyl β-D-glucopyranoside and mixed with liposomes supplemented with 5.6 mol% cholesterol to produce proteoliposomes of defined size, which showed negligible leakage of internal substrates. Transport experiments with proteoliposomes revealed a counter-exchange of glucose 1-phosphate (Glc1P), glucose 6-phosphate (Glc6P), inorganic phosphate (Pi), 3-phosphoglycerate and dihydroxyacetone phosphate. The Glc1P/Pi counter-exchange reaction exhibited an apparent Km for Glc1P of 0.4 mM. Glc6P was a competitive inhibitor of Glc1P transport (Ki 0.8 mM), and the two hexose phosphates could exchange with each other, indicating the operation of a single carrier protein. Glc1P/Pi antiport in proteoliposomes showed an exchange stoichiometry at pH 8.0 of 1 mol of phosphate transported per mol of sugar phosphate.

Download Full-text

Transport of Inorganic Phosphate in the Marine SeagrassPosidonia OceanicaBy32P-Phosphate As Tracer

Chemistry and Ecology ◽

10.1080/02757549608039095 ◽

1996 ◽

Vol 12 (4) ◽

pp. 287-295

Author(s):

P. Orlando ◽

G. Queirazza ◽

L. Guzzi ◽

R. Trenta ◽

R. Trevisi ◽

...

Keyword(s):

Inorganic Phosphate ◽

Transport Of Inorganic Phosphate

Download Full-text

How Renal Phosphate Transport Is Regulated

Physiology ◽

10.1152/physiologyonline.1987.2.2.45 ◽

1987 ◽

Vol 2 (2) ◽

pp. 45-48

Author(s):

H Murer ◽

M Kerstin

Keyword(s):

Protein Synthesis ◽

Inorganic Phosphate ◽

Apical Membrane ◽

Phosphate Transport ◽

Short Term ◽

Transcellular Transport ◽

Sodium Dependent ◽

Transport Of Inorganic Phosphate ◽

Cotransport System

Transcellular transport of inorganic phosphate (Pi) in the renal proximal tubule is sodium dependent. The entry step across the apical membrane involves a Na-Pi cotransport system and is subject to short-term and long-term regulation. This regulation can be protein synthesis independent (short term) as well as protein synthesis dependent (long term).

Download Full-text