We investigated phosphoenolpyruvate-dependent phosphotransferase system enzyme II activities for sucrose and glucose in Streptococcus mutans 6715g. Two integral membrane proteins, enzyme IIscr and enzyme IIglc, each specific for its sugar substrate, sucrose or glucose, were identified by their abilities to catalyze specific sugar:sugar-phosphate exchange reactions. Some of the properties of the...

Introduction: The placenta expresses significant amounts of insulin and IGF1 receptors at distinct locations on both fetal maternal surfaces. This makes the receptor accessible to and/or insulin, IGF2. IGFs are involved in receptor-mediated regulation placental growth transport, angiogenesis. Maternal obesity during gestation mediates changes metabolism mothers, placentas as well growth. Object...

The p66(Shc) protein isoform regulates MAP kinase activity and the actin cytoskeleton turnover, which are both required for normal glucose transport responses. To investigate the role of p66(Shc) in glucose transport regulation in skeletal muscle cells, L6 myoblasts with antisense-mediated reduction (L6/p66(Shc)as) or adenovirus-mediated overexpression (L6/p66(Shc)adv) of the p66(Shc) protein w...

L6 muscle cells survive long-term (18 h) disruption of oxidative phosphorylation by the mitochondrial uncoupler 2,4-dinitrophenol (DNP) because, in response to this metabolic stress, they increase their rate of glucose transport. This response is associated with an elevation of the protein content of glucose transporter isoforms GLUT3 and GLUT1, but not GLUT4. Previously we have reported that t...

To reinvestigate the "hydrolase-related transport" concept, neutral α-d-glucosidase, a membrane-bound disaccharidase of renal proximal tubule, was first purified from brush-border membranes and then asymmetrically reincorporated into egg phosphatidylcholine vesicles. Proteolytic treatments and immunotitration studies demonstrated that this enzyme was integrated in native and artificial membrane...

facilitative transport of glucose across animal cell membranes is mediated by members of the Glut protein family (1). These 50-to 60-kDa glyco-proteins are ubiquitously expressed in mammalian tissues and are responsible for the uptake of sugar from the blood into cells, supplying cellular glucose for ATP production and for a wide variety of anabolic reactions. Additionally, glucose transport in...

Osmotic shock is a procedure in which Gram-negative bacteria are treated as follows. First they are suspended in 0.5 M sucrose containing ethylenediaminetetraacetate. After removal of the sucrose by centrifugation, the pellet of cells is rapidly dispersed in cold, very dilute, MgCl(2). This causes the selective release of a group of hydrolytic enzymes. In addition, there is selective release of...

The regulation by glucose and insulin of the muscle-specific facilitative glucose transport system GLUT-4 was investigated in L6 muscle cells in culture. Hexose transport activity, mRNA expression, and the subcellular localization of the GLUT-4 protein were analyzed. As observed previously (Walker, P. S., Ramlal, T., Sarabia, V., Koivisto, U.-M., Bilan, P. J., Pessin, J. E., and Klip, A. (1990)...

Cholera toxin, in contrast to its stimulatory action on adenylate cyclase, renders the insulin-stimulated adipose cell insensitive to the inhibitory actions of lipolytic agents such as isoprenaline, adrenocorticotropic hormone or glucagon. Conversely, pertussis toxin eliminates both the stirnulatory actions of the antilipolytic agents, such as adenosine, nicotinic acid, and prostaglandin E , , ...