N-Bromoacetylethanolamine Phosphate as a Probe for the Identification of a Liver Microsomal Glucose-6-Phosphate Transporter Peptide in Rats and Ehrlich Ascites Tumor-Bearing Mice

• Published in: Archives of biochemistry and biophysics 2000-05, Vol.377 (1), p.115-121
• Main Authors: Foster, James D., Stevens, Andrew L., Nordlie, Robert C.
• Format: Article
• Language: English
• Subjects: Affinity Labels - metabolism; Affinity Labels - pharmacology; Animals; Antiporters - antagonists & inhibitors; Antiporters - metabolism; Biological Transport - drug effects; Carcinoma, Ehrlich Tumor - metabolism; Diphosphates - metabolism; Ehrlich ascites tumor-bearing mice; Ethanolamines - metabolism; Ethanolamines - pharmacology; glucose-6-phosphatase; Glucose-6-Phosphatase - antagonists & inhibitors; Glucose-6-Phosphatase - metabolism; Glucose-6-Phosphate - metabolism; glucose-6-phosphate transporter; Hydrolysis - drug effects; liver microsomes; Male; Mice; Microsomes, Liver - chemistry; Microsomes, Liver - drug effects; Microsomes, Liver - metabolism; Molecular Weight; Monosaccharide Transport Proteins - antagonists & inhibitors; Monosaccharide Transport Proteins - metabolism; N-bromoacetylethanolamine phosphate; Peptides - chemistry; Peptides - metabolism; Permeability - drug effects; Rats; Time Factors; tosyl-lysine chloromethyl ketone; Tosyllysine Chloromethyl Ketone - pharmacology
• ISSN: 0003-9861; 1096-0384
• DOI: 10.1006/abbi.2000.1763

Hepatic microsomal glucose-6-phosphatase is a multicomponent system composed of substrate/product translocases and a catalytic subunit. Previously we (Foster et al. (1996) Biochim. Biophys. Acta 12, 244–254) demonstrated that N-bromoacetylethanolamine phosphate (BAEP) is a time-dependent, irreversible inhibitor of glucose-6-phosphate hydrolysis in intact but not disrupted microsomes. We proposed that BAEP manifests its inhibitory effect by binding with a glucose-6-phosphate translocase protein of the glucose-6-phosphatase system. Here we provide additional evidence that BAEP inhibits glucose-6-phosphate transport in microsomal vesicles and utilize [32P]BAEP as an affinity label in the identification of a glucose-6-phosphate transport protein. In this study, we identify 51-kDa rat and mouse liver microsomal proteins involved in glucose-6-phosphate transport into and out of microsomal vesicles by utilizing (1) an Ehrlich ascites tumor-bearing mouse model, which displays a decreased sensitivity to the time-dependent inhibitory effect of BAEP, and (2) another glucose-6-phosphate translocase inhibitor, tosyl-lysine chloromethyl ketone, in conjunction with [32P]BAEP as an affinity label.