Impermeant maleimides. Identification of an exofacial component of the human erythrocyte hexose transport mechanism.

Localization of a reactive exofacial sulfhydryl on the glucose carrier of human erythrocytes

“…Of the two other major carrier isoforms, the liver/islet (Thorens et al, 1988;Permutt et al, 1989) has, but the so-called "insulin-regulatable" (James et al, 1989) carrier lacks, a corresponding cysteine. Our previous demonstration (May, 1985) that the impermeant sulfhydryl reagent glutathione-maleimide-I (Batt et al, 1976) inhibited insulin-stimulated glucose transport in isolated rat adipocytes may have been caused in part by reaction with the eryth-roid/brain carrier also present in that cell type (James et al, 1989), or by interference with the insulin receptor-carrier coupling mechanism. The ability to selectively modify the erythroid/brain carrier on an exofacial sulfhydryl in the presence of other carrier subtypes may be useful in determining the relative amounts of different carriers functioning in the plasma membrane.…”

“…These results concur with the predictions of hydropathy analysis and will be relevant for studies of how modification of this sulfhydryl affects carrier function, particularly since several other known carrier isoforms lack a corresponding cysteine. e facilitative glucose carrier of human erythrocytes has an exofacial sulfhydryl which is reactive with a variety of sulfhydryl reagents which either do not penetrate the cell membrane (Batt et al, 1976;Roberts et al, 1982;May, 1987May, , 1989a or do so very slowly (May, 1989b). In addition to its exposure on the cell surface, this group has several features + Supported by Research Grants DK38794, DK07061, and RR05424 from the National Institutes of Health.…”

Maltosyl isothiocyanate: an affinity label for the glucose transporter of the human erythrocyte membrane. 1. Inhibition of glucose transport

“…Phutrakul & Jones, 1979) or band 4.5 (Kahlenberg & Zala, 1977; Goldin & Rhoden, 1978;Batt et al, 1976;Abbot & Schachter, 1976;Zoccoli et al, 1978) as the carrier. In this paper we present evidence that may reconcile the observations of all investigators.…”

“…46,54], the transporter. The types of compounds used have been substrate analogue covalent affinity labels (Taverna & Langdon, 1973b;Trosper & Levy, 1977), nonspecific covalent inhibitors such as maleimides (Batt et al, 1976) and fluorodinitrobenzene (Jung & Carlson, 1975), and a bound reversible inhibitor, cytochalasin B, in conjunction with differential membrane extraction and fluorodinitrobenzene labeling (Lienhard et al, 1977;Zoccoli et al, 1978; Jung & Rampal, 1977;Pinkovsky et al, 1978). The second general approach has been to extract, purify, and isolate a specific membrane protein which, when reassociated with a lipid bilayer, conferred upon it stereospecific glucose transport (Kasahara & Hinckle, 1976, 1977 Kahlenberg, 1976;Zala & Kahlenberg, 1976; Jones & Nickson, 1978; Goldin & Rhoden, 1978; Shanahan & Czech, 1977a,b;Phutrakul & Jones, 1979).…”

Monosaccharide transport system of the human erythrocyte. Identification of the cytochalasin B binding component

“…The results reported here are in agreement with those of three other recent investigations aimed at the identification and isolation of protein components of the monosaccharide transport system. Batt et al (1976) have identified a component that migrates in the band 4.5 region of polyacrylamide gels through the differential labeling of intact erythrocytes with an impermeant maleimide. Both cytochalasin B and D-glucose served as protecting agents.…”