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*

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

STUDY DESIGN: Posterior and posterolateral fusions were performed in rabbit lumbar spines. OBJECTIVES: To investigate the osteoinductive effect of polyphosphates. SUMMARY AND LITERATURE REVIEW: Inorganic polyphosphates are known to be rich in osteoblasts and involved in the mineralization process in bone metabolism. However, no study has been undertaken to investigate the osteoinductive effect of polyphosphates. MATERIALS AND METHODS: Forty adult New Zealand white rabbits underwent monolevel lumbar fusions, and were divided into two groups according to the fusion beds: twenty each between the laminae (posterior fusion group, PF group) and between the transverse processes (posterolateral fusion group, PLF group). In ten of twenty rabbits in the PF group, 0.8gm of autogenous iliac bone was grafted onto the right sides of the laminae, which were used as a control group (C1), with 0.4gm autogenous bone immersed in polyphosphate solution in the left sides as an experimental group (E1). In the other ten, 0.8gm of autogenous bone was grafted onto the right sides (C2) and 0.8gm of tricalcium phosphate porous blocks containing polyphosphate in the left sides (E2). The other twenty rabbits of the PLF group were similarly divided into C1, E1, C2 and E2 groups by grafting the same amount of materials between the transverse processes. The animals were sacrificed at the 16th postoperative week and the fusions evaluated grossly, radiologically and histologically. Statistical differences between the groups (C1 vs. E1, C2 vs. E2 and E1 vs. E2) in each of the PF and PLF groups were compared by chi-square tests. RESULTS: The fusions were finally determined by the gross finding using manual palpation. In the PF group, bony fusions were obtained in 90, 80, 90 and 70% of the C1, E1, C2 and E2 groups, respectively. In the PLF group, these were 80, 70, 60 and 0% of the C1, E1, C2 and E2 groups, respectively. Statistical analysis revealed differences only between C2 and E2 (p=0.005), and between E1 and E2 (p=0.002) of the PLF group. Histologically, beta-tricalcium phosphate particles containing polyphosphate were transformed into the osteoid in some areas of the PLF-E2 group, although only fibrous unions were obtained grossly. CONCLUSIONS: It is suggested that the polyphosphate may have an osteoinductive effect, even though the osteoinductive potency was very week in this fusion model of the rabbit lumbar spine. Therefore, further explorations, such as the threshold and optimal concentrations of polyphosphate in vivo and the best carrier material of polyphosphate, should be performed to obtain the optimal conditions for fusion.
Adult ; Animals ; Bone Regeneration ; Humans ; Metabolism ; Osteoblasts ; Palpation ; Polyphosphates ; Rabbits ; Spine* ; Transplants

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

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