Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Multiple forms of glucose-adenosine triphosphate phosphotransferase in rat mammary gland.

ABSTRACT: Measurements have been made of the total hexokinase activity and of the relative amounts of types I and II hexokinase in rat mammary gland and at different stages of the lactation cycle. The total hexokinase activity increased during lactation, that of type II increasing to a greater extent than that of type I; the type II/type I activity ratio rose from a pregnancy value of about 1 to a mid-lactation value of 3, returning to 1 on involution. The changes in type II hexokinase activity during the lactation cycle parallel the changes in the insulin sensitivity of mammary-gland tissue. A study of the effect of alloxan-diabetes on mammary-gland hexokinase during the mid-lactation period revealed that, although the total glucose-phosphorylating capacity of the mammary gland was almost unchanged, the relative contributions of type I and type II hexokinases altered, decreasing the type II/type I activity ratio to about 1.

SUBMITTER: Walters E

PROVIDER: S-EPMC1271219 | biostudies-other | 1967 Sep

REPOSITORIES: biostudies-other

ACCESS DATA

Json Xml

Similar Datasets

Brain adenosine 5'-triphosphate-creatine phosphotransferase.

Project description:1. The purification of creatine kinase (ATP-creatine phosphotransferase, EC 2.7.3.2) from ox brain by a method that is quicker, simpler and gives much higher yields than other published procedures is described. 2. Stoicheiometric inhibition studies with iodoacetate showed that the enzyme, like that from muscle, has two reactive thiol groups that are essential for enzyme activity. 3. The amino acid sequence around the essential thiol groups was determined and found to be virtually identical with that in creatine kinases from rabbit and ox muscle, and very similar to that found in arginine kinase; the evolutionary significance of this is discussed. 4. The identification of DNS-amino acids on thin layers of silica gel was found to have, in many cases, distinct advantages over that on polyamide layers.

| S-EPMC1179640 | biostudies-other

Further properties and possibel mechanism of action of adenosine 5'-triphosphate-D-glucose 6-phosphotransferase from rat liver.

Project description:1. Magnesium ions are the most effective bivalent ions in the glucokinase reaction. 2. The molecular weight of rat hepatic glucokinase is 48000-49000 as assessed by gel filtration on Sephadex G-100. 3. Anomalous kinetic behaviour at low glucose concentrations appears to be due to the formation during the purification procedure of fragments possessing modified catalytic properties, but is unlikely to be of physiological significance. 4. Extension of previous studies (Parry & Walker, 1966) suggests that glucokinase catalyses a reaction of the random Bi Bi type similar to that of yeast hexokinase. 5. The inhibitory effects of various thiol reagents suggest that a thiol group may be involved at or near the binding site of the acceptor molecule.

| S-EPMC1198334 | biostudies-other

Glucose transporter expression in rat mammary gland.

Project description:The expression of different glucose transporter isoforms was measured during the development and differentiation of the rat mammary gland. Before conception, when the mammary gland is mainly composed of adipocytes, Glut 4 and Glut 1 mRNAs and proteins were present. During pregnancy, the expression of Glut 4 decreased progressively, whereas that of Glut 1 increased. In the lactating mammary gland only Glut 1 was present, and was expressed at a high level. The absence of Glut 4 suggests that glucose transport is not regulated by insulin in the lactating rat mammary gland.

| S-EPMC1131712 | biostudies-other

Adenosine 5'-triphosphate-arginine phosphotransferase from lobster muscle.

Project description:1. The amino acid composition of lobster-muscle arginine kinase is given and discussed briefly. 2. The results were used to calculate a partial specific volume of 0.735. 3. The results are compared with the amino acid composition of creatine kinase.

| S-EPMC1264971 | biostudies-other

Some properties of rat-liver glucose--adenosine triphosphate phosphotransferases.

Project description:In normal rat liver hexokinase (EC 2.7.1.1) activity usually accounts for not more than 30% of the total glucose-ATP phosphotransferase activity, the remainder being due to glucokinase (EC 2.7.1.2). In the present work it was found that in normal rat liver the relative activities of these two enzymes were occasionally very different from those usually found even though the total glucose-ATP phosphotransferase activity was within the normal range. In some cases almost the entire glucose-ATP phosphotransferase was accounted for by the low-K(m) enzyme hexokinase. Some properties of this enzyme system are reported. It is suggested that this shift in favour of the low-K(m) enzyme without change in the total glucose-ATP phosphotransferase activity may represent a regulatory mechanism.

| S-EPMC1265217 | biostudies-other

Adenosine 5'-triphosphate-arginine phosphotransferase from lobster muscle. Molecular weight.

Project description:1. The molecular weight of arginine kinase from lobster muscle has been determined by three procedures: ultracentrifuge analysis, gel filtration and density-gradient centrifugation. 2. The three methods give similar results and the best estimate of the molecular weight is 37000. 3. The enzyme does not readily show association-dissociation phenomena. 4. The usefulness of density-gradient centrifugation for determinations of molecular weight is briefly discussed.

| S-EPMC1264970 | biostudies-other

ADENOSINE 5'-TRIPHOSPHATE-ARGININE PHOSPHOTRANSFERASE FROM LOBSTER MUSCLE: PURIFICATION AND PROPERTIES.

Project description:1. A simple chromatographic method is described for the purification of arginine kinase from lobster (Homarus vulgaris) muscle. 2. Some physical properties and the effects on enzyme activity of ionic strength, pH, buffer salts, metal ions and substrates are reported. 3. The kinetic parameters, evaluated by variation of the concentration of one of the substrates, are dependent on the concentration of the other substrate. 4. The properties of the enzyme are discussed in relation to previous findings about phosphagen phosphotransferases.

| S-EPMC1206586 | biostudies-other

The mechanism of the reaction catalysed by adenosine triphosphate-creatine phosphotransferase.

Project description:1. The forward and reverse reactions catalysed by ATP-creatine phosphotransferase have been studied kinetically at pH8.0 in the presence and absence of products, under conditions in which the free Mg(2+) concentration was maintained constant at 1mm. Thus at fixed pH the reaction may be considered as being bireactant and expressed as:MgATP(2-)+creatine(0)right harpoon over left harpoonMgADP(-)+phosphocreatine(2-)2. The initial-velocity pattern in the absence of products and the product-inhibition pattern have been determined. These are consistent with a random mechanism in which all steps are in rapid equilibrium except that concerned with the interconversion of the central ternary complexes, and in which two dead-end complexes (enzyme-MgADP-creatine and enzyme-MgATP-phosphocreatine) are formed. The results are in accord with previous suggestions that the enzyme possesses distinct sites for the combination of the nucleotide and guanidino substrates. 3. Values have been determined for the Michaelis and dissociation constants involved in the combination of each substrate with various enzyme forms. Although these values cannot be regarded as absolute, they appear to indicate that the presence of one substrate on the enzyme enhances the combination of the second substrate. In addition, it would seem that in the formation of the enzyme-MgADP-creatine complex the concentration of one reactant does not affect the combination of the other. This contrasts with the formation of the enzyme-MgATP-phosphocreatine complex, where each reactant hinders the combination of the other.

| S-EPMC1264541 | biostudies-other

Simultaneous Detection of Adenosine Triphosphate and Glucose Based on the Cu-Fenton Reaction.

Project description:Both adenosine triphosphate (ATP) and glucose are important to human health, and their abnormal levels are closely related to angiocardiopathy and hypoglycaemia. Therefore, the simultaneous determination of ATP and glucose with a single test mode is highly desirable for disease diagnostics and early recognition. Herein, a new fluorescence on/off switch sensing platform is developed by carbon nanodots (CNDs) to detect ATP and glucose simultaneously. The fluorescence of CNDs can be quenched by Cu2+ and hydrogen peroxide (H?O?), due to the formation of hydroxyl radicals (·OH) produced in the Cu-Fenton reaction. Based on the high affinity of Cu2+ with ATP, the fluorescence of CNDs will recover effectively after adding ATP. Additionally, glucose can be efficiently catalyzed by glucose oxidase (GOx) to generate H?O?, so the platform can also be utilized to analyze glucose. Under optimum conditions, this sensing platform displays excellent sensitivity and the linear ranges are from 0.1 to 7 μM for ATP with a limit of detection (LOD) of 30.2 nM, and from 0.1 to 7 mM for glucose with a LOD 39.8 μM, respectively. Benefiting from the high sensitivity and selectivity, this sensing platform is successfully applied for simultaneous detection of ATP and glucose in human serum samples with satisfactory recoveries.

| S-EPMC6069456 | biostudies-literature

Theory of Polymer Entrapped Enzyme Ultramicroelectrodes: Application to Glucose and Adenosine Triphosphate Detection.

Project description:We validate, by comparison with experimental data, a theoretical description of the amperometric response of microbiosensors formed via enzyme entrapment. The utility of the theory is further illustrated with two relevant examples supported by experiments: (1) quantitative detection of glucose and (2) quantitative detection of adenosine triphosphate (ATP).

| S-EPMC2863125 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data