Cover of: Hydration, conformational states and kinetics of yeast hexokinase PII | Amanda Bradford

Hydration, conformational states and kinetics of yeast hexokinase PII

  • 100 Pages
  • 4.86 MB
  • English
Brock University, Dept. of Biological Sciences , St. Catharines, Ont
Glucokinase., Hydration., Chemical kine
Statementby Amanda Bradford.
The Physical Object
Paginationxi, 100 leaves :
ID Numbers
Open LibraryOL23362927M

Nisms postulated for yeast hexokinase, we undertook studies of the reaction with a kinetic approach. It will be shown that the results obtained are in harmony with the mechanism suggested by Trayser and Colowick (5).

The enzyme-phosphate (2) and enzyme-glucose. When ATP, the normal phosphate donor for hexokinase D ('glucokinase'), is replaced by ITP, the positive co-operativity with respect to glucose disappears.

Description Hydration, conformational states and kinetics of yeast hexokinase PII FB2

This may be rationalized in relation to kinetic models for hexokinase D co-operativity, which assume Cited by: 9.

Activators of Yeast Hexokinase Vol. No. 8 pH q r pH CT pH 0 pH 1 I I I I I I I I I I I I I I 5 IO 15 Pi,mM FIG. Effect of pH on the activation of yeast hexokinase by Pi.

Conditions were the same as those in Fig. 1, except that. Purified yeast hexokinase PII (EC ) has previously been shown to exhibit negative cooperativity with MgATP and a burst-type of slow transient d Cited by:   Hexokinase or glucokinase is an enzyme that convert glucose to glucose 6 phosphate.

It is the first step of glycolysis. One ATP molecule is cleaved to ADP and the phosphate released is added to glucose. Hence glucose is converted to glucose 6 phosphate. This enzyme which convert glucose to conformational states and kinetics of yeast hexokinase PII book 6 phosphate exists in two isomer forms.

Increased stability and catalytic efficiency of yeast hexokinase upon interaction with zwitterionic micelles.

Details Hydration, conformational states and kinetics of yeast hexokinase PII FB2

Kinetics and conformational studies of the yeast hexokinase isoforms, PI and PII. Table 1 presents data on the effect of glycerol, erythritol, xylitol, and sorbitol on the thermal denaturation of hexokinase A at pH monitored by DSC.

The thermal denaturation transition curve for the enzyme in the buffer, used as a control, has been provided in Fig. Fig. 1 also includes data for the effect of sorbitol on the thermal denaturation of hexokinase A, used as a Cited by: Hexokinase undergoes and induced-fit conformational change when it binds to glucose, which ultimately prevents the hydrolysis of ATP.

It is also allosterically inhibited by physiological concentrations of its immediate product, glucosephosphate. This is a mechanism by which the influx of substrate into the glycolytic pathway is controlled.

Correlation between glucose/fructose discrepancy and hexokinase kinetic properties in different Saccharomyces cerevisiae wine yeast strains February. pH-dependent effects of Cr(NH3)2ATP on kinetics of yeast hexokinase PII. Relationship to the slow transition mechanism.

Peters BA, Neet KE. The effect of Cr(NH3)2ATP, a virtually inert, inner sphere metal-ligand complex, on the kinetics of purified yeast hexokinase PII Cited by: 6.

Carbon catabolite repression in yeast depends on catalytic active hexokinase isoenzyme PII (Entian a). A yeast strain lacking hexokinase isoenzymes PI and PII was transformed, using a recombinant pool with inserts of yeast nuclear DNA up to 10 kbp in length.

One hundred transformants for hexokinase were obtained. All selected plasmids coded for hexokinase isoenzyme PII, none for Cited by: I.U.B.: C.A.S.: Enzymatic Reaction (image will open in a new window).

Hexokinase catalyzes the reaction: Hexokinases have been isolated from the yeast cell in two distinct forms, designated P-I and P-II (Schulze et al. ).These are separate, noninterconvertible isozymes (Womack et al. Hexokinase is used to determine glucose, fructose, mannose and ATP.

Hexokinase from Saccharomyces cerevisiae lyophilized powder, ≥ units/mg protein, Protein ≥10 % by biuret Synonym: ATP: D-Hexosephosphotransferase, Hexokinase from yeast CAS Number Enzyme Commission (EC) Number (BRENDA | IUBMB) EC Number MDL number MFCD [email protected] NACRES NA   Mutants with reduced hexokinase activity previously isolated as resistant to carbon catabolite repression of invertase and maltase (Zimmermann and Scheel, ) were allele tested with mutant strains of Lobo and Maitra () which had defects in one or several of the genes coding for glucokinase and the two unspecific hexokinases.

It could be demonstrated, that the mutation Cited by: in the first stage of glycolysis, glucose is phosphorylated by hexokinase, isomerized by PGI (phosphoglucose isomerase) hosphorylated by PFK (phosphofructokinase), and cleaved by aldolase to yield the triodes GAP and DHAP, which are interconverted by TIM (triose phosphate isomerase).

these reactions con sue 2 ATP per glucose. yeast hexokinase, mM [14C]glucose 6-phosphate ( X IO6 cpm/Fmol), and 50 mM Pipes, pH 7, in mL was added to 10 mL of a rapidly stirring solution containing 50 mM Pipes, pH 7, 50 mM glucose 6-phosphate, and various levels of MgADP. Samples were isolated and counted by the same procedure as was used for the forward reaction partitioning.

Ohning, G., and Neet, K.: 6-(p-Toluidinyl)naphthalenesulfonic Acid as a Fluorescent Probe of Yeast Hexokinase: Conformational States Induced by Sugar and. A genetic disease characterized by the inability to convert galactose to glucose, which can lead to a buildup of toxic metabolic by-products.

Increased galactose concentration in the blood results in a higher galactose concentration in the lens of the eye, where the sugar is reduced to galactitol. Hexokinase VS Glucokinase: Both of these enzymes are iso enzymes, which means that both of them have the same chemical natures and have same action but have different physical properties and site of action etc.

Here are some of the difference betw. Information on EC - hexokinase for references in articles please use BRENDA:EC Please wait a moment until all data is loaded. This message will disappear when all data is loaded.

EC Tree 2 Transferases Transferring phosphorus-containing groups. Hexokinase (Hexa +kinase) as the name suggests is an enzyme (kinase) that acts upon hexose or six carbon sugars i.e.

Download Hydration, conformational states and kinetics of yeast hexokinase PII FB2

glucose. Hexokinase phosphorylates hexoses (transfer an inorganic phosphate group from ATP to a hexose) and form hexose phosphate.

Other articles where Hexokinase is discussed: metabolism: Glycolysis: In most cells a hexokinase with a high affinity for glucose—i.e., only small amounts of glucose are necessary for enzymatic activity—effects the reaction.

In addition, the liver contains a glucokinase, which requires a much greater concentration of glucose before it reacts. Glucokinase functions only in emergencies, when. hexokinase method: the most specific method for measuring glucose in serum or plasma, wherein hexokinase plus ATP transforms glucose to glucose 6-phosphate plus ADP; glucose 6-phosphate is then reacted with NADP and glucose 6-phosphate dehydrogenase to form NADP which is measured spectrophotometrically.

D-Glucose, D-mannose, D-fructose, sorbitol and D-glucosamine can act as acceptors; ITP and dATP can act as donors. The liver isoenzyme has sometimes been called glucokina. mately 30% identical to that of yeast hexokinase A, as derived from its cDNA (Figure 1) and a refined model of the crystal structure of glucose-bound yeast hexokinase A (HDB et al., unpublished data).

The secondary structure for hexokinase I is essentially identical to that of the yeast enzyme as it was first presented by Steitz and colleagues File Size: KB. Ans: The binding of glucose to hexokinase induces a conformation change that brings the amino acid residues that facilitate the phosphoryl transfer into position in the active site.

Binding of water alone does not induce this conformational change. Examples of enzymatic reactions Pages: Difficulty: 3 Why is a transition-state analog not necessarily the same as a competitive inhibitor.

When several structures of yeast hexokinase were solved in the 's, this was shown to be true. Hexokinase is shaped like a clamp, with a big groove in one side (shown in the figure with an arrow).

The structure without glucose (PDB entry 2yhx) is open, allowing access to the active site. Glucokinase (EC ) is an enzyme that facilitates phosphorylation of glucose to inase occurs in cells in the liver and pancreas of humans and most other each of these organs it plays an important role in the regulation of carbohydrate metabolism by acting as a glucose sensor, triggering shifts in metabolism or cell function in response to rising or Aliases: GCK, FGQTL3, GK, GLK, HHF3, HK4.

Enzymatic Assay of HEXOKINASE FINAL ASSAY CONCENTRATIONS: In a 3 ml reaction mix, the final concentrations are mM glycylglycine, 17 mM ATP, % cresol red, 14 mM magnesium chloride, 27 mM glucose and 1 unit hexokinase. REFERENCE Darrow, R.A., and Colowick, S.P. () Methods in Enzymology V, NOTES: 1.

reagents is mM NAD +, mM ATP, unit/ml of hexokinase and unit/ml of glucosephosphate dehydrogenase with sodium benzoate and potassium sorbate as preservatives. Store any unused reagent at ºC for up to 4 weeks. Prepare the samples as recommended in the manufacturer’s instructions 1.

The sample should be inFile Size: 52KB. Hexokinase is found in the mitochondrial membrane. Hexokinase transfers the terminal phosphate of ATP to carbon 3 of glucose.

Hexokinase consists of two domains, or lobes, that come together when glucose and the MgATP2 complex are bound. Hexokinase is a type of phosphatase that catalyzes the transfer of a phosphoryl group from ATP to a hexose.

Abstract. The hexokinase isoenzyme 2 of Saccharomyces cerevisiae (ScHxk2) represents an archetype of a two-domain protein with the active site located in a cleft between the two g of the substrate glucose results in a rigid body movement of the two domains leading to a cleft closure of the active by: 4.

About Hexokinases Hexokinases are group of enzymes of transferase family (EC ), with very wide range of molecular weight, from 40 to kDa, that catalyze transfer of phosphate group from ATP molecule to D-glucose or other D-hexoses.

The overall reaction can be written as ATP + D-hexose = ADP + D-hexose 6-phosphate. This enzyme is very important because it involved into .