
	Where results make sense

Topic: Hexokinase

In the News (Fri 21 Nov 08)

Norm Coleman

Benji Madden

Freddie Mac

Puerto Rico

Vladimir Putin

Treasury Department

Mitt Romney

Giovanni Trapattoni

Steve Ballmer

James Bond

	Hexokinase (Site not responding. Last check: 2007-10-22)
		Hexokinase is active on glucose, mannose and fructose (Nwagwu and Opperdoes, 1982; Hara et al., 1997), for which it has similar affinities and on which it acts with similar rates.
		However, mannose 6-phosphate, that is produced inside the glycosome by the action of hexokinase is metabolised only very slowly, probably because of the low activity of mannose-6-phosphate isomerase in the glycosome (Misset and Opperdoes, unpublished), and thus accumulates inside the organelle, leading to an inhibition of glycolysis (Hara et al., 1997).
		Hexokinase is not inhibited by either glucose 6-phosphate or glucose 1,6-bisphosphate (Nwagwu and Opperdoes 1982; Opperdoes and Van Roy, unpublished), as are the hexokinases from most other sources, but it is selectively inhibited by a number glucose analogues (Trinquier et al., 1995; Willson and Opperdoes, unpublished).
	www.icp.ucl.ac.be /~opperd/review/hexo.html (418 words)

	Diabetes: Allosteric Regulation of Glycogen Synthase and ... @ HighBeam Research (Site not responding. Last check: 2007-10-22)
		At the end of the study, the rats were anesthetized and rectus abdominis and heart muscles were freeze-clamped in situ with aluminum tongues precooled in liquid nitrogen for measurement of the glycogen concentration, hexokinase and glycogen synthase activities, rates of glycogen synthesis from glucose and glucosamine, and metabolite concentrations.
		Hexokinase activity was measured at a low glucose concentration (0.125 mmol/l), which resulted in negligible accumulation of G-6-P itself.
		Hexokinase activity in the absence of GlcN6P was set at 100%.
	www.highbeam.com /library/doc0.asp?DOCID=1G1:54772190&refid=ip_encyclopedia_hf (5933 words)

	Hexokinase -- Facts, Info, and Encyclopedia article (Site not responding. Last check: 2007-10-22)
		They are categorized as actin fold proteins, sharing a common (A nucleotide derived from adenosine that occurs in muscle tissue; the major source of energy for cellular reactions) ATP binding site core surrounded by more variable sequences that determine substrate affinities and other properties.
		Several hexokinase isoforms or (Click link for more info and facts about isozyme) isozymes providing different functions can occur in a single ((biology) taxonomic group whose members can interbreed) species.
		Hexokinases I and II follow (Click link for more info and facts about Michaelis-Menten kinetics) Michaelis-Menten kinetics at physiologic concentrations of substrates.
	www.absoluteastronomy.com /encyclopedia/h/he/hexokinase.htm (602 words)

	Specificity of liver hexokinase
		Although the statement that hexokinase D is not inhibited by glucose 6-phosphate might be objectionable in a mechanistic context, the reference here is clearly to the physiological role.
		The other hexokinases have high affinities for glucose relative to its concentration in blood (i.e., they are half-saturated at concentrations of less than 0.1 mM).
		Because hexokinase D activity is not inhibited by glucose 6-phosphate, this enzyme contributes significantly to the liver’s capacity to regulate blood glucose.
	bip.cnrs-mrs.fr /bip10/liverhk.htm (1309 words)

	John Wilson - Faculty in MSU Biochemistry and Molecular Biology
		Hexokinase catalyzes the initial step in metabolism of glucose, and regulation of hexokinase activity is generally recognized as a major factor governing the rate of cerebral glucose metabolism.
		However, hexokinase binds to the outer mitochondrial membrane and there is clear evidence that this physical association leads to close metabolic interactions with intramitochondrial oxidative phosphorylation, and that this is also of regulatory significance.
		The levels of hexokinase vary markedly in different brain regions, and are generally correlated with basal levels of glucose utilization.
	www.bch.msu.edu /faculty/wilson.htm (411 words)

	hexokinase (introduction)
		These three types of mammalian hexokinases appear to have evolved from an ancestral hexokinase of 50 kDa, by gene duplication and fusion; consequently, they have extensive sequence repetition, both between them and between their N-terminal and C-terminal regions.
		Hexokinase I exhibits a unique regulatory property: physiological levels of inorganic phosphate (Pi) can reverse the inhibition of Glc phosphorylation effected by Glc-6-P. This characteristic defines hexokinase I as an enzyme with a catabolic role, while the other hexokinases are considered to have mainly an anabolic role.
		This supports the fact that hexokinase I is particularly abundant in highly energy-demanding cells, as brain and red blood cells.
	www.arches.uga.edu /~epavan/bcmb8010 (421 words)

	Carbon Source-Dependent Phosphorylation of Hexokinase PII and Its Role in the Glucose-Signaling Response in Yeast -- ... (Site not responding. Last check: 2007-10-22)
		Hexokinase activity was carried out as described by Bergmeyer (2) with fructose as substrate.
		The residual enzymatic phosphorylation activity of hexokinase II mutants is correlated with glucose repression in Saccharomyces cerevisiae.
		The 15 N-terminal amino acids of hexokinase II are not required for in vivo function: analysis of a truncated form of hexokinase II in Saccharomyces cerevisiae.
	mcb.asm.org /cgi/content/full/18/5/2940 (5470 words)

	Pfam 18.0 : Hexokinase_1 (Site not responding. Last check: 2007-10-22)
		Hexokinase is an important enzyme that catalyses the ATP-dependent conversion of aldo- and keto-hexose sugars to the hexose-6-phosphate (H6P).
		There are three isozymes of hexokinase in yeast (PI, PII and glucokinase): isozymes PI and PII phosphorylate both aldo- and keto-sugars; glucokinase is specific for aldo-hexoses.
		Type IV hexokinase is similar to the yeast enzyme in containing only the two domains, and is sometimes incorrectly referred to as glucokinase.
	pfam.wustl.edu /cgi-bin/getdesc?name=Hexokinase_1 (762 words)

	Isozymes of mammalian hexokinase: structure, subcellular localization and metabolic function -- Wilson 206 (12): 2049 ... (Site not responding. Last check: 2007-10-22)
		In contrast, the rate of Glc phosphorylation by mitochondrially bound hexokinase (squares) is insensitive to increasing levels of extramitochondrial ATP produced by non-hexokinase-bearing mitochondria, consistent with the view that the mitochondrially bound enzyme is restricted to intramitochondrial ATP, produced by the mitochondria to which the enzyme is bound, as substrate.
		The rate of Glc phosphorylation by mitochondrially bound hexokinase, using intramitochondrially generated ATP as substrate, is correlated with the rate of oxidative phosphorylation.
		BeltrandelRio, H. and Wilson, J. Hexokinase of rat brain mitochondria: relative importance of adenylate kinase and oxidative phosphorylation as sources of substrate ATP, and interaction with intramitochondrial compartments of ATP and ADP.
	jeb.biologists.org /cgi/content/full/206/12/2049 (5543 words)

	Overexpression of Arabidopsis Hexokinase in Tomato Plants Inhibits Growth, Reduces Photosynthesis, and Induces Rapid ...
		Hexokinase activity of control wild-type plants (1.8 and 7 nmol/mg protein/min for glucose and fructose, respectively), which is a result of endogenous native hexose phosphorylating enzymes, was determined as 100%.
		hexokinase activity is necessary to express the phenotypes.
		Entian, K.D. (1980) Genetic and biochemical evidence for hexokinase PII as a key enzyme involved in carbon catabolite repression in yeast.
	www.plantcell.org /cgi/content/full/11/7/1253 (6401 words)

	At3g20040 - hexokinase, putative (Site not responding. Last check: 2007-10-22)
		At3g20040 is a homologue of Hk1 (Hexokinase, type I) from Mus musculus.
		At3g20040 is a homologue of HK1 (Hexokinase, type I) from Homo sapiens.
		At3g20040 is a homologue of HXK2 (Hexokinase B) from Saccharomyces cerevisiae.
	www.ihop-net.org /UniPub/iHOP/gg/6904.html (132 words)

	Changes in leaf hexokinase activity and metabolite levels in response to drying in the desiccation-tolerant species ... (Site not responding. Last check: 2007-10-22)
		Hexokinases (EC 2.7.1.1) catalyse the conversion of glucose,
		Hexokinase activity (glucose substrate) in (A) Sporobolus stapfianus and (B) Xerophyta viscosa leaf tissue at different RWCs over an 18 d and a 21 d dehydration period, respectively.
		Antisense repression of Hexokinase I leads to an overaccumulation of starch in leaves of transgenic potato plants but not to significant changes in tuber carbohydrate metabolism.
	jxb.oxfordjournals.org /cgi/content/full/52/358/961 (4380 words)

	Inhibition of early apoptotic events by Akt/PKB is dependent on the first committed step of glycolysis and ... (Site not responding. Last check: 2007-10-22)
		The inhibition of apoptosis by overexpression of hexokinase I
		Beutner, G., Ruck, A., Riede, B., and Brdiczka, D. Complexes between porin, hexokinase, mitochondrial creatine kinase and adenylate translocator display properties of the permeability transition pore: Implication for regulation of permeability transition by the kinases.
		Robey, R.B., Raval, B.J., Ma, J., and Santos, A.V. Thrombin is a novel regulator of hexokinase activity in mesangial cells.
	www.genesdev.org /cgi/content/full/15/11/1406 (7400 words)

	Subcellular distribution and kinetic properties of cytosolic and non-cytosolic hexokinases in maize seedling roots: ... (Site not responding. Last check: 2007-10-22)
		Subcellular distribution and kinetic properties of cytosolic and non-cytosolic hexokinases in maize seedling roots: implications for hexose phosphorylation -- da-Silva et al.
		Subfractionation of cytosolic and non-cytosolic maize root hexokinases.
		Iijima K, Awazi N. Histochemical studies on the morphology of the Golgi apparatus and on distribution of hexokinase and some enzymes concerning vitamin C synthesis in substantia nigra of the rabbit.
	jxb.oxfordjournals.org /cgi/content/full/52/359/1191 (5181 words)

	Glycolysis
		The phosphorylation accomplishes two goals: First, the hexokinase reaction converts nonionic glucose into an anion that is trapped in the cell, since cells lack transport systems for phosphorylated sugars.
		Four mammalian isozymes of hexokinase are known (Types I - IV), with the Type IV isozyme often referred to as glucokinase.
		hexokinases, and as a consequence their viability is protected.
	web.indstate.edu /thcme/mwking/glycolysis.html (4507 words)

	Crystal Structures of Escherichia coli ATP-Dependent Glucokinase and Its Complex with Glucose -- Lunin et al. 186 (20): ... (Site not responding. Last check: 2007-10-22)
		The mechanism of regulation of hexokinase: new insights from the crystal structure of recombinant human brain hexokinase complexed with glucose and glucose-6-phosphate.
		Refinement of yeast hexokinase B co-ordinates and sequence at 2.1 Å resolution.
		Hexokinase 2 from Saccharomyces cerevisiae: regulation of oligomeric structure by in vitro phosphorylation at serine-14.
	jb.asm.org /cgi/content/full/186/20/6915 (5818 words)

	The Bifunctional Role of Hexokinase in Metabolism and Glucose Signaling -- Harrington and Bush 15 (11): 2493 -- THE ...
		hexokinase senses free glucose in a linear, concentration-dependent
		DelaFuente, G., and Sols, A. The kinetics of yeast hexokinase in the light of induced fit involved in the binding of its sugar substrate.
		Xiao, W.-Y., Sheen, J., and Jang, J.-C. The role of hexokinase in plant sugar signal transduction and growth and development.
	www.plantcell.org /cgi/content/full/15/11/2493 (2454 words)

	Hexokinase Isozyme Distribution in Human Skeletal Muscle -- Ritov and Kelley 50 (6): 1253 -- Diabetes
		I and hexokinase II were 37 and 63%, respectively (Table 2).
		Sui D, Wilson JE: Structural determinants for the intracellular localization of the isozymes of mammalian hexokinase: intracellular localization of fusion constructs incorporating structural elements from the hexokinase isozymes and the green fluorescent protein.
		Beutner G, Ruck A, Brdiczka D: Complexes between hexokinase, mitochondrial porin and adenylate translocator in brain: regulation of hexokinase, oxidative phosphorylation and permeability transition pore.
	diabetes.diabetesjournals.org /cgi/content/full/50/6/1253 (6646 words)

	Glycolysis & Fermentation
		The Hexokinase reaction involves nucleophilic attack of the C6 hydroxyl oxygen of glucose on the phosphorous of the terminal phosphate of ATP.
		The enzyme undergoes a substrate-induced conformational change similar to that of Hexokinase.
		Product inhibition of Hexokinase ensures that cells will not continue to accumulate glucose from the blood, if [glucose-6-phosphate] within the cell is ample.
	www.rpi.edu /dept/bcbp/molbiochem/MBWeb/mb1/part2/glycolysis.htm (1469 words)

	Hexokinase inhibitors (US5854067)
		The latter group of agents includes inactive hexokinases and fragments thereof that retain mitochondrial binding functions and hexokinase-glucokinase chimeras that further substitute glucokinase activity for hexokinase activity.
		Mammalian cells including such hexokinase inhibitors, methods of making such cells and various in vitro and in vivo methods of using cells with reduced hexokinase activity are also described herein.
		Xie and Wilson, "Rat brain hexokinase: the hydrophobic N-terminus of the mitochondrially bound enzyme is inserted in the lipid bilayer," Arch Biochem.
	www.delphion.com /details?pn=US05854067__&language=en (1775 words)

	Human protein: P78542 - Hexokinase 1 (EC ) (Fragment). EMBL Bioinformatic Harvester
		Hexokinases phosphorylate glucose to produce glucose-6-phosphate, thus committing glucose to the glycolytic pathway.
		This gene encodes a ubiquitous form of hexokinase which localizes to the outer membrane of mitochondria.
		hexokinase is an allosteric enzyme inhibited by its product glc-6-p.
	harvester.embl.de /harvester/P785/P78542.htm (795 words)

	Metabolic Profiling of Transgenic Tomato Plants Overexpressing Hexokinase Reveals That the Influence of Hexose ...
		Total hexokinase activities of extracts from fully expanded tomato leaves and from the pericarp of tomato fruit harvested 30 (green), 45 (orange), and 60 (red) d after flowering.
		Characterization and compartmentation, in green leaves, of hexokinases with different specificities for glucose, fructose and mannose and for nucleotide triphosphates.
		Sindelar L, Sindelarova M, Burketova L (1998) Hexokinases of tobacco leaves: influence of plant age on particulate and soluble isozyme composition.
	www.plantphysiol.org /cgi/content/full/133/1/84 (7398 words)

	Worthington Hexokinase (Site not responding. Last check: 2007-10-22)
		Hexokinases have been isolated from the yeast cell in two distinct forms, designated P-I and P-II (Schulze et al.
		Hexokinase is used to determine glucose, fructose, mannose and ATP.
		ATP and ITP have been demonstrated to transphosphorylate in the yeast hexokinase reaction (Martinez 1961).
	www.worthington-biochem.com /HK (1517 words)

	Hexokinase Structures (Site not responding. Last check: 2007-10-22)
		The initial display shows superimposed models of hexokinase in the "Open" (without glucose) and "Closed" (+ glucose) conformations.
		When the amino acid sequence of yeast hexokinase is aligned with that of S.
		The yeast hexokinase structure and the comparison to the S.
	info.bio.cmu.edu /courses/03231/ProtStruc/hexokinase.htm (350 words)

Try your search on: Qwika (all wikis)