Adenosine triphosphate (ATP) regeneration systems are essential for efficient biocatalytic phosphoryl transfer reactions. Polyphosphate kinase (PPK) is a versatile enzyme that can transfer phosphate groups among adenosine monophosphate (AMP), adenosine diphosphate (ADP), ATP, and polyphosphate (Poly P). Utilization of PPK is an attractive solution to address the problem of ATP regeneration due to its ability to use a variety of inexpensive and stable Poly P salts as phosphate group donors. This review comprehensively summarizes the structural characteristics and catalytic mechanisms of different types of PPKs, as well as the variations in enzyme activity, catalytic efficiency, stability, and coenzyme preference observed in PPKs from different sources. Moreover, recent advances in PPK-mediated ATP regeneration systems and protein engineering of wild-type PPK are summarized.
Adenosine Triphosphate/metabolism* ; Adenosine Monophosphate ; Polyphosphates/metabolism* ; Catalysis ; Regeneration

Polyphosphate kinase plays an important role in the catalytic synthesis of ATP in vitro. In order to find a polyphosphate kinase that can efficiently synthesize ATP using short-chain polyphosphate (polyP) as substrate, the polyphosphate kinase 2 (PPK2) from Sphingobacterium siyangensis was cloned and expressed in Escherichia coli BL21(DE3). As an enzyme for ATP regeneration, PPK2 was used in combination with l-amino acid ligase (YwfE) to produce l-alanyl-l-glutamine (Ala-Gln). The length of ppk2 of S. siyangensis is 810 bp, encoding 270 amino acids. The SDS-PAGE showed that PPK2 was expressed correctly and its molecular weight was 29.7 kDa as expected. The reaction conditions of PPK2 were optimized. PPK2 could maintain good activity in the range of 22-42 ℃ and pH 7-10. The highest enzyme activity was observed at 37 ℃, pH 7, 30 mmol/L magnesium ion (Mg²⁺), 5 mmol/L ADP and 10 mmol/L sodium hexametaphosphate, and the yield of ATP reached 60% of the theoretical value in 0.5 hours at this condition. When used in combination with YwfE to produce Ala-Gln, the PPK2 showed a good applicability as an ATP regeneration system, and the effect was similar to that of direct addition of ATP. The PPK2 from S. siyangensis shows good performance in a wide range of temperature and pH, synthesizes ATP with cheap and readily available short chain polyP as substrate. The PPK2 thus provides a new enzyme source for ATP dependent catalytic reaction system.
Sphingobacterium/metabolism* ; Phosphotransferases (Phosphate Group Acceptor)/metabolism* ; Amino Acids ; Adenosine Triphosphate ; Regeneration ; Polyphosphates/metabolism*

OBJECTIVE: To establish a quantitative fluorescent detection method using DAPI for detecting inorganic polyphosphate (polyP) in enterohemorrhagic Escherichia coli (EHEC) O157:H7. METHODS: The DNA of wild-type strain of EHEC O157:H7 was extracted and purified. DAPI was combined with the extracted DNA and polyP45 standards for measurement of the emission spectra at 360 nm and 415 nm fluorescence spectrophotometry. The fluorescence of DAPI-DNA and DAPI-polyP complexes was detected by fluorescence confocal microscopy to verify the feasibility of DAPI for detecting polyP. To determine the optimal pretreatment protocol for improving the cell membrane permeability, the effects of 6 pretreatments of the cells (namely snap-freezing in liquid nitrogen, freezing at -80 ℃, and freezing at -20 ℃, all followed by thawing at room temperature; heating at 60 ℃ for 10 min; treatment with Triton x-100; and placement at room temperature) were tested on the survival of EHEC O157:H7. The fluorescence values of the treated bacteria were then measured after DAPI staining. A standard calibration curve of polyP standard was established for calculation of the content of polyP in the live cells of wildtype EHEC strain and two mutant strains. RESULTS: At the excitation wavelength of 360 nm, the maximum emission wavelength of DAPI-DNA was 460 nm, and the maximum emission wavelength of DAPI-polyP was 550 nm at the excitation wavelength of 415 nm. The results of confocal microscopy showed that 405 nm excitation elicited blue fluorescence from DAPIDNA complex with the emission wavelength of 425-475 nm; excitation at 488 nm elicited green fluorescence from the DAPIpolyP complex with the emission wavelength of 500-560 nm of. Snap-freezing of cells at -80 ℃ followed by thawing at room temperature was the optimal pretreatment to promote DAPI penetration into the live cells. The standard calibration curve was =1849+127.5 (R=0.991) was used for determining polyP content in the EHEC strains. The experimental results showed that wild-type strain had significantly higher polyP content than the mutant strains with deletion. CONCLUSIONS We established a convenient quantitative method for direct and reliable detection polyP content to facilitate further study of polyP and its catalytic enzymes in EHEC O157:H7.
Escherichia coli O157 ; Escherichia coli Proteins ; Polyphosphates

To explore the effect of long-time propofol infusion on myocardial enzymes, mitochondrial cytochrome C and ATP in rabbits. 
 Methods: A total of 18 New Zealand rabbits were randomly divided into 3 groups: a control group, a propofol group and an intralipid group. The rabbits were continuously infused with 0.9% normal saline in the control group, 1% propofol in the propofol group, and 10% intralipid in the intralipid group, respectivey. The arterial blood was collected at 0, 8, 16 h and the end of experiment to examine creatine kinase (CK) and creatine kinase isoenzyme (CK-MB). In the end, the myocardial mitochondria from myocardial tissues was separated by differential centrifugation, and mitochondrial cytochrome C content and adenosine triphosphate (ATP) levels were examined by high performance liquid chromatography.
 Results: Compared with the control group, the release of cytochrome C from mitochondria were increased in the propofol group and the intralipid group (both P<0.05), but there was no significant difference between them (P>0.05). There was also no significant difference in the ATP content of the mitochondria among the 3 groups (P>0.05). The levels of CK were increased at 8, 16 and 24 h after infusion in the propofol group and the intralipid group compared with that before the infusion (all P<0.05); compared with the control group, the levels of CK were increased at 8, 16 and 24 h after infusion in the propofol group and the intralipid group (all P<0.05); compared with the intralipid group, the levels of CK were increased at 8, 16 and 24 h after infusion in the propofol group (all P>0.05); compared with the control group, the levels of CK-MB were obviously increased in the infusion of propofol for 24 h in the propofol group (P<0.05).
 Conclusion: The levels of serum CK increase after the infusion of propofol and intralipid for a long time, and the levels of CK-MB also elevate in the infusion of propofol. Propofol and intralipid can increase the release of myocardial mitochondrial cytochrome C, but they don't affect the ATP production in myocardial mitochondrial.
Adenosine Triphosphate ; metabolism ; Animals ; Creatine Kinase ; blood ; metabolism ; Creatine Kinase, MB Form ; blood ; metabolism ; Cytochromes c ; metabolism ; Emulsions ; administration & dosage ; pharmacology ; Infusions, Intravenous ; Mitochondria ; drug effects ; Myocardium ; chemistry ; enzymology ; Phospholipids ; administration & dosage ; pharmacology ; Polyphosphates ; Propofol ; administration & dosage ; pharmacology ; Rabbits ; Soybean Oil ; administration & dosage ; pharmacology

With glucose as substrate, sodium tripolyphosphate as the phosphorus acylating agent, and phosphorylase of Solanum tuberosum as the catalyst, glucose 1-phosphate was synthesized. Based on a three-level, three-variable Box-Behnken experimental design, response surface methodology was used to evaluate the effects of temperature, molar ratio of glucose to sodium tripolyphosphate and time on the production. The structure of the product was confirmed by 1H NMR spectra. The results show that the optimum conditions were as follows: temperature 35 degrees C, molar ratio of glucose to sodium tripolyphosphate 1.35:1 and time 19 h.
Catalysis ; Glucose ; metabolism ; Glucosephosphates ; biosynthesis ; Phosphorylases ; metabolism ; Polyphosphates ; chemistry ; Solanum tuberosum ; enzymology ; Surface Properties

Adenosine triphosphate (ATP)-sensitive potassium (KATP) channels in pancreatic beta-cells play a crucial role in insulin secretion and glucose homeostasis. These channels are composed of two subunits: a pore-forming subunit (Kir6.2) and a regulatory subunit (sulphonylurea receptor-1). Recent studies identified large number of gain of function mutations in the regulatory subunit of the channel which cause neonatal diabetes. Majority of mutations cause neonatal diabetes alone, however some lead to a severe form of neonatal diabetes with associated neurological complications. This review focuses on the functional effects of these mutations as well as the implications for treatment.
Adenosine Triphosphate ; Glucose ; Homeostasis ; Insulin ; KATP Channels ; Polyphosphates ; Potassium

Cyanide poisoning can occur from industrial disasters, smoke inhalation from fire, food, and multiple other sources. Cyanide inhibits mitochondrial oxidative phosphorylation by blocking mitochondrial cytochrome oxidase, which in turn results in anaerobic metabolism and depletion of adenosine triphosphate in cells. Rapid administration of antidote is crucial for life saving in severe cyanide poisoning. Multiple antidotes are available for cyanide poisoning. The action mechanism of cyanide antidotes include formation of methemoglobin, production of less or no toxic complex, and sulfane sulfur supplementation. At present, the available antidotes are amyl nitrite, sodium nitrite, sodium thiosulfate, hydroxocobalamin, 4-dimethylaminophenol, and dicobalt edetate. Amyl nitrite, sodium nitrite, and 4-dimethylaminophenol induce the formation of methemoglobin. Sodium thiosulfate supplies the sulfane sulfur molecule to rhodanese, allowing formation of thiocyanate and regeneration of native enzymes. Hydroxocobalamin binds cyanide rapidly and irreversibly to form cyanocobalamin. Dicobalt edetate acts as a chelator of cyanide, forming a stable complex. Based on the best evidence available, a treatment regimen of 100% oxygen and hydroxocobalamin, with or without sodium thiosulfate, is recommended for cyanide poisoning. Amyl nitrite and sodium nitrite, which induce methemoglobin, should be avoided in victims of smoke inhalation because of serious adverse effects.
Adenosine Triphosphate ; Aminophenols ; Amyl Nitrite ; Antidotes* ; Disasters ; Edetic Acid ; Electron Transport Complex IV ; Equipment and Supplies ; Fires ; Hydroxocobalamin ; Inhalation ; Metabolism ; Methemoglobin ; Oxidative Phosphorylation ; Oxygen ; Poisoning ; Polyphosphates ; Regeneration ; Smoke ; Sodium ; Sodium Nitrite ; Sulfur ; Thiocyanates ; Thiosulfate Sulfurtransferase ; Thiosulfates ; Vitamin B 12

Breast cancer is the most common malignancy, and it is also the major cause of cancer-related deaths of women worldwide. Breast cancer treatment involves surgery, chemotherapy, radiation therapy, or combination therapy, and novel strategies are needed to boost the oncologic outcome. The non-metabolizable glucose analogue, 2-deoxy-D-glucose (2-DG) which inhibits glucose synthesis and adenosine triphosphate production, is one of the important discoveries involving the disturbances that can be caused to the process of the metabolism. The glucose analogue, 2-DG, is known as a tumor sensitizer to irradiation (IR) and chemotherapy, which help improve the treatment rates. It enhances the cytotoxicity via oxidative stress, which is more redundant in tumor cells than in normal ones. This article provides a brief summary on studies related to 2-DG chemo-/radio-sensitization effects by combination therapy of 2-DG/IR or 2-DG/doxorubicin.
Adenosine Triphosphate ; Breast ; Breast Neoplasms ; Cell Line, Tumor ; Combined Modality Therapy ; Deoxyglucose ; Female ; Glucose ; Humans ; Oxidative Stress ; Polyphosphates ; Radiation Tolerance

Erlotinib is a low-molecular-weight quinazoline derivative that inhibits the activation of epidermal growth factor receptor (EGFR) tyrosine kinase through competitive binding of the adenosine triphosphate binding domain of the receptor. Patients undergoing anti-EGFR therapy frequently present with cutaneous reactions like a sterile follicular and pustular rash, xerosis, pruritus, paronychia, hair abnormalities and mucositis, which can cause serious discomfort and negatively affect the compliance with anti-EGFR therapy. We report here on an interesting case of hair abnormalities induced by erlotinib (Tarceva(R)) and this presented as eyelash lengthening and hair curling in a 62-year-old woman.
Adenosine Triphosphate ; Binding, Competitive ; Compliance ; Exanthema ; Female ; Hair ; Humans ; Middle Aged ; Mucositis ; Paronychia ; Polyphosphates ; Protein-Tyrosine Kinases ; Pruritus ; Quinazolines ; Receptor, Epidermal Growth Factor ; Erlotinib Hydrochloride

This study is to prepare scopolamine hydrobromide nanoparticles-in-microsphere system (SH-NiMS) and evaluate its drug release characteristics in vitro. SH nanoparticles were prepared by ionic crosslinking method with tripolyphosphate (TPP) as crosslinker and chitosan as carrier. Orthogonal design was used to optimize the formulation of SH nanoparticles, which took the property of encapsulation efficiency and drug loading as evaluation parameters. With HPMC as carrier, adjusted the parameters of spray drying technique and sprayed the SH nanoparticles in microspheres encaposulated by HPMC was formed and which is called nanoparticles-in-microsphere system (NiMS). SH-NiMS appearances were observed by SEM, structure was obsearved by FT-IR and the release characteristics in vitro were evaluated. The optimized formulation of SH nanoparticles was TPP/CS 1:3 (w/w), HPMC 0.3%, SH 0.2%. The solution peristaltic speed of the spray drying technique was adjusted to 15%, and the temperature of inlet was 110 degrees C. The encapsulation product yeild, drug loading and particle sizes of SH-NiMS were 94.2%, 20.4%, and 1256.5 nm, respectively. The appearances and the structure of SH-NiMS were good. The preparation method of SH-NiMS is stable and reliable to use, which provide a new way to develop new dosage form.
Chitosan ; chemistry ; Cross-Linking Reagents ; Delayed-Action Preparations ; Drug Carriers ; chemistry ; Drug Compounding ; methods ; Microscopy, Electron, Scanning ; Microspheres ; Nanoparticles ; chemistry ; Particle Size ; Polyphosphates ; chemistry ; Scopolamine Hydrobromide ; administration & dosage ; chemistry ; Spectroscopy, Fourier Transform Infrared