Molecular size of a Na sup + -dependent amino acid transporter in Ehrlich ascites cell plasma membranes estimated by radiation inactivation

Journal Article · Tue Apr 16 04:00:00 EDT 1991 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00229a016· OSTI ID:5592690

McCormick, J I; Johnstone, R M ^[1]; Jette, M; Beliveau, R ^[2]; Potier, M ^[3]

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1. McGill Univ., Montreal, Quebec (Canada)
2. Universite du Quebec a Montreal (Canada)
3. Univ. de Montreal, Quebec (Canada)

Radiation inactivation was used to estimate the molecular size of a Na{sup +}-dependent amino acid transport system in Ehrlich ascites cell plasma membrane vesicles. Na{sup +}-dependent {alpha}-aminoisobutyric acid uptake was measured after membranes were irradiated at {minus}78.5C in a cryoprotective medium. Twenty-five percent of the transport activity was lost at low radiation doses (<0.5 Mrad), suggesting the presence of a high molecular weight transport complex. The remaining activity ({approximately}75% of total) decreased exponentially with increasing radiation dose, and a molecular size of 347 kDa was calculated for the latter carrier system. Radiation doses 2-3 fold higher than those required to inactivate amino acid transport were needed to cause significant volume changes. The relationship between the fragmentation of a 120-130-kDapeptide, a putative component of the Na{sup +}-dependent amino acid carrier and loss of transport activity in irradiated membranes was also examined. Peptide loss was quantitated by Western blot analysis. The data support the conclusion that fragmentation of the 120-130-kDa peptide is related to loss of amino acid transport in irradiation Ehrlich cell plasma membranes.

• OSTI ID: 5592690
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 30:15; ISSN 0006-2960; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

560120* -- Radiation Effects on Biochemicals
Cells
&amp; Tissue Culture
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMAL CELLS
ASCITES TUMOR CELLS
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
CARBON 14 COMPOUNDS
CARBON COMPOUNDS
CELL CONSTITUENTS
CELL MEMBRANES
ELECTROMAGNETIC RADIATION
GAMMA RADIATION
HYDROGEN COMPOUNDS
INACTIVATION
IONIZING RADIATIONS
LABELLED COMPOUNDS
MEMBRANE PROTEINS
MEMBRANE TRANSPORT
MEMBRANES
ORGANIC COMPOUNDS
PROTEINS
RADIATION EFFECTS
RADIATIONS
SURVIVAL CURVES
TRITIUM COMPOUNDS
TUMOR CELLS