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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Crystalline adenylate kinase from porcine muscle cytosol can assume two interconvertible structures. Here, we report the refined structure of crystal form B at 3.3 A resolution and compare it with crystal form A. Crystal forms A and B can be interconverted by protonation and deprotonation of His36, which is located deep in the active center cleft. The changes concern the molecular packing as well as the polypeptide chain conformation. On conversion from crystal form A to B, the N-terminal alpha-helix unwinds, the active center cleft opens to some extent and the nucleotide-binding glycine-rich loop 15-22 at the active center is detached from the bulk protein. This loop has counterparts in various important mononucleotide-binding proteins and is known to bind a phosphoryl group in adenylate kinase and in the oncogenic ras proteins. It is most likely involved in the phosphoryl transfer and the concomitant conformational changes. it is suggested that the two observed conformations are relevant for enzyme action in solution: they represent two of a series of three known snapshots depicting the enzyme during the substrate binding process.
J Mol Biol 1988 Oct 20
PMID:The switch between two conformations of adenylate kinase. 285 Mar 68

A subcellular fraction enriched 12 times in glycosomes (NAD+-linked alpha-glycerophosphate dehydrogenase) and devoid of detectable contamination from other subcellular components, was prepared from bloodstream Trypanosoma rhodesiense. Using a method employing exposure to toluene as a means of studying normally latent glycosomal enzymes, and phospholipase A2 as a membrane probe, the association of adenylate kinase and alpha-glycerophosphate dehydrogenase with the glycosome was studied. The normally latent glycerophosphate dehydrogenase (NAD+ linked), it is proposed, is an intraglycosomal enzyme having no membrane association, but bound to the core by weak ionic linkages. As such it is possible to release the enzyme from permeable (toluene treated) glycosomes using Cl-, with a resulting 4-fold increase in the Km for dihydroxyacetone phosphate. The presence of Cl- also stimulates an increase in specific activity, but this is observed before any release of enzyme. In contrast adenylate kinase, a non-latent glycosomal enzyme, is clearly membrane associated, the use of phospholipase A2 revealing an absolute dependence on phospholipid for activity. Restoration of activity appears to specifically require phosphatidyl choline and to be co-operative in nature (nH = 1.56). It is proposed that adenylate kinase is an integral glycosomal membrane enzyme, probably affecting the control of intra-glycosomal ADP/ATP levels.
Mol Biochem Parasitol 1985 Feb
PMID:The presence of alpha-glycerophosphate dehydrogenase (NAD+-linked) and adenylate kinase as core and integral membrane enzymes respectively in the glycosomes of Trypanosoma rhodesiense. 298 83

A combination of selective spin decoupling, two-dimensional double quantum spectroscopy, correlated spectroscopy (COSY), and pH titration experiments brought about the assignment of all tyrosyl spin systems and completed the assignment of the histidyl spin systems in porcine adenylate kinase. In the detection of the tyrosyl spin systems it proved to be advantageous to resort to the COSY method rather than to two-dimensional double quantum spectroscopy. In the titration experiments, His189 revealed a second apparent pK value at pH 8.3, which is explained by deprotonation of the adjacent residue Cys187. None of the seven tyrosyl side-chains shows any evidence for deprotonation up to the point of denaturation of the protein, which took place around pH 10.
J Mol Biol 1985 Mar 20
PMID:Assignment of aromatic spin systems in the 1H nuclear magnetic resonance spectrum of adenylate kinase. 298 13

In the three-dimensional model of adenylate kinase, the phosphate-binding site for AMP and ATP has been identified [Pai, E.F. et al. (1977) J. Mol. Biol. 114, 37--45]. In this region one can distinguish a sequence glycine XXXX glycinelysine. The same sequence is found in many other mononucleotide-binding proteins including elongation factors and oncogenic P21 proteins. Dinucleotide-binding proteins display a pyrophosphate-binding unit with a glycine pattern different from that of mononucleotide-binding proteins. It has been found that P21 ras protein possesses a strand motif typical for (pyro)phosphate binding of a mononucleotide. A single mutation at position 12 can confer oncogenic activity on the protein. Based on the assumption that amino acid residues which are critical for function are preferentially conserved, we predict from the sequence that glycine residue 15 rather than residue 12 is important for (pyro)phosphate binding.
 ...
PMID:Phosphate-binding sequences in nucleotide-binding proteins. 298 3

The loss of the catabolic products of adenosine triphosphate in the form of purine nucleosides and oxypurines during ischemia and subsequent reperfusion may limit adenine nucleotide regeneration. This study compared the effects of infusion of inhibitors of the major reactions involved in the degradation of adenosine triphosphate to inosine on the postischemic recovery of high energy phosphate and myocardial function. Inhibitors of adenylate kinase, 5'nucleotidase, adenosine translocase and adenosine deaminase were studied. Following 30 minutes of ischemia, only hearts infused with alpha, beta, methylene adenosine diphosphate (5' nucleotidase inhibitor) recovered significantly better ventricular function than control (p less than 0.05), but all hearts had increased adenosine triphosphate regeneration (p less than 0.05). The formation and washout of greater than 30% of the total adenine pool metabolites was not prevented by any drug. Nevertheless all manipulations of adenine metabolism resulted in recruitment of high energy phosphate during preischemic infusion.
J Mol Cell Cardiol 1986 Oct
PMID:The influence of inhibitors of the ATP degradative pathway on recovery of function and high energy phosphate after transient ischemia in the rat heart. 302 47

Covalent coupling of protein by crosslinking reagents have been used to study the interaction of mitochondrial creatine kinase (CKm) and hexokinase (HK) with the mitochondrial membranes. The effects of crosslinkers were studied either by following the inhibition of solubilization of enzymatic activities or by modification of the electrophoretic patterns of proteins solubilized from mitochondria after treatment with different crosslinkers. Dimethylsuberimidate (DMS) efficiently reduced the amount of HK activity solubilized by various agents but it did not modify solubilization of CKm from mitochondria. The effect of DMS on HK solubilization did not result from non specific crosslinking since it did not impede the solubilization of adenylate kinase. Bissuccinimidyl another class of crosslinker has been tested. Ethyleneglycol bis (succinimidyl succinate)(EGS) efficiently reduced HK solubilization, but in addition it induced osmotic stabilization of mitochondria and thus impeded release of soluble or solubilized proteins from the intermembrane space. Furthermore this agent drastically inhibited CKm activity and thus, in a second set of experiments the effect of crosslinkers have been studied by the disappearance of protein bands in the electrophoretic pattern of soluble fractions obtained from mitochondria, the outer membranes of which have been ruptured to allow free release of soluble proteins. Results of these experiments showed that succinimidyl reagents and Cu++-Phenanthroline substantially reduced the amount of CKm released from mitochondria and confirmed that bisimidates were ineffective in inhibiting CKm solubilization. In addition crosslinking reagents have been used to study subunits interactions in purified CKm. Our results showed, in contrast with control experiments with a non oligomeric protein (ovalbumin) which did not give rise to polymers, that in the same conditions electrophoresis of crosslinked CKm resolved a set of species with molecular weights roughly equal to integral multiples of the protomer. These results proved that the polymeric form of CKm was an octamer.
Mol Cell Biochem 1987 Dec
PMID:Interaction of creatine kinase and hexokinase with the mitochondrial membranes, and self-association of creatine kinase: crosslinking studies. 344 Dec 51

Regulation of coronary flow as a function of myocardial energy expenditure was investigated in isolated perfused rat hearts electrically paced at the desired frequencies. The sinoatrial node was excised to lower the endogenous heart rate. The main covariants measured were phosphagen, inorganic phosphate, adenosine, inosine and hypoxanthine concentrations in the tissue, washout of nucleosides and hypoxanthine into the perfusate, oxygen consumption and coronary flow. Oxygen consumption was linearly correlated with heart rate and coronary flow, while the correlation between coronary flow and perfusate adenosine was nonlinear. The adenosine concentrations in the tissue and perfusate showed a mirror image curvilinearity reminiscent of a threshold pattern for adenosine washout. The tissue adenosine content had a negative linear correlation with the adenylate phosphorylation potential (long(ATP/ADP X Pi)). Adenosine output was linearly correlated with free AMP concentration in the tissue, the latter being calculated from the equilibrium of the adenylate kinase reaction. The results confirm the correlation between cellular energy state and coronary flow and support the notion that the mediators between the former and the vascular smooth muscle involve the concentration of free AMP in the tissue, suggesting that the formation of adenosine may be limited by the availability of AMP. The results are in agreement with the hypothesis that adenosine is the diffusible extracellular mediator in the energy-linked regulation of coronary flow.
J Mol Cell Cardiol 1986 Nov
PMID:Role of cellular energy state and adenosine in the regulation of coronary flow during variation in contraction frequency in an isolated perfused heart. 379 75

Endothelial cells which cover the inner wall of blood vessels were extracted for bioluminescence analyses of nucleotides and enzymes. The contaminating blood was removed by heparinization and rinsing with ammonium chloride. The content of the endothelial cells of the rat aorta was reached by time governed laminar elution, using a saponin solution to disrupt the cell membranes. Uniformity of extraction was achieved with a Hamilton programmable pump. All the analyses of the eluted fractions showed a characteristic and reproducible peak. The activities of glucose-6-phosphate dehydrogenase and adenylate kinase were significantly higher in the diabetic animals whereas the amount of nucleotides did not differ between diabetic and control rats. The laminar elution technique combined with bioluminescence assay represents a new approach to studies of biochemical alterations in the endothelial cells. The method is also useful for extraction and analyses of other surface layers.
Mol Cell Biochem 1987 Jan
PMID:A new approach to the biochemical pathology of the vascular system, using time governed laminar elution and bioluminescence analyses. 380 99

The conversion of cyclohexanecarboxyl-CoA to hippuric acid in submitochondrial fractions from guinea pig liver was studied using a gas chromatographic-mass spectrometric method employing selected ion monitoring. Comparison of the activities of the cyclohexanecarboxyl-CoA to hippuric acid converting system (CCoAHC-system) and marker enzymes in the various submitochondrial fractions showed that the CCoAHC-system is localized in the mitochondrial matrix. Partial separation of the inner and outer membranes has been accomplished by treating mitochondria with digitonin in isotonic medium and fractionating the treated mitochondria by differential centrifugation. A digitonin-protein ratio of 2.6 mg of digitonin/10 mg of protein must be used in order to release significant amounts of amine oxidase activity (outer membrane marker) from low speed mitochondrial pellets. This pellet still contained most of the glutamate dehydrogenase activity and was insignificantly contaminated with adenylate kinase. Moderate concentrations of phenazine methosulfate (PMS) greatly stimulated the activity of the CCoAHC-system, even in intact mitochondria (optimal concentration of PMS: 1 mM) whilst higher concentrations (greater than 1 mM) decreased the activity. The formation of hippuric acid in these mitochondrial preparations was linear with time for at least 40 min and linear with respect to protein concentration up to approximately 2.0 mg mitochondrial protein X ml-1.
Mol Cell Biochem 1985 Jul
PMID:The aromatization of cyclohexanecarboxyl-CoA to hippuric acid by guinea pig liver mitochondria: submitochondrial localization. 404 29

Pure frog retina rod outer segments (ROS) preparations (A280/A500 = 2,1-2,3) catalyze the synthesis of ATP from ADP in the presence of Mg2+. Adenylate kinase (AK) (ATP:AMP phosphotransferase, EC 2.7.4.3) specific activities for ROS preparations are within the range 2-4 mumole per hour for mg protein. The enzymatic activity of investigated preparations is due to intact, but not destroyed ROS. The component which possesses AK is found in water-soluble, but not in membranous ROS fractions and seems to be a part of the predominant ROS plasma protein--GTP-binding complex of transducin. It has been shown, that this component is the T beta subunit of transducin and its enzymatic activity is controlled by other subunits of the transducin complex. The obtained results indicate that GDP kinase (ATP:GDP phosphotransferase, EC 2.7.4.6) activity of transducin depends on the work of both of T beta and T alpha subunits. It has been shown that in the ROS preparations synthesis of the ATP from ADP and GDP phosphorylation are stimulated by a lowering of Ca2+ concentration (less than 10(-5)-10(-7) M). T beta component is suggested to play the role of phosphotransferase which phosphorylates GDP associated with the T alpha subunits and it leads to formation of a complex T alpha X GTP which is an activator of vertebrate retina ROS phosphodiesterase.
Mol Biol (Mosk)
PMID:[Adenylate kinase and GDP-kinase activity of rod outer segments in the frog retina. Possible functional role of the T beta subunit of transducin]. 608 68


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