scholarly journals The contents of adenine nucleotides, phosphagens and some glycolytic intermediates in resting muscles from vertebrates and invertebrates

1975 ◽  
Vol 152 (1) ◽  
pp. 23-32 ◽  
Author(s):  
I Beis ◽  
E A Newsholme
Keyword(s):  
Honey Bee ◽  
Adenylate Kinase ◽  
Flight Muscle ◽  
Insect Flight ◽  
Adenine Nucleotides ◽  
Equilibrium Constants ◽  
Pectoral Muscle ◽  
Energy Utilization ◽  
Mass Action ◽  
Concentration Ratios

1. The lowest contents of ATP and the lowest ATP/AMP concentration ratios are observed in the molluscan muscles that have very low rates of energy expenditure during contraction. The highest contents of ATP are observed in the extremely aerobic insect flight muscle and the extremely anaerobic pectoral muscle of the pheasant and domestic fowl. In general, the lowest ATP/AMP concentration ratios are observed for muscle in which the variation in the rate of energy utilization is small (e.g. some molluscan muscles, heart muscle); the highest ratios are observed in muscles in which this variation is large (lobster abdominal muscle, pheasant pectoral muscle, some insect flight muscles). This finding is consistent with the proposed role of AMP and the adenylate kinase reaction in the regulation of glycolysis. However, in the flight muscle of the honey-bee the ATP/AMP ratio is very low, so that glycolysis may be regulated by factors other than the variation in AMP concentration. The variation in the contents of arginine phosphate in muscle from the invertebrates is much larger than the variation in creatine phosphate in muscle from the vertebrates. The contents of hexose monophosphates and pyruvate are, in general, higher in the muscles of vertebrates than in those of the invertebrates. The contents of phosphoenolpyruvate are similar in all the muscles investigated, except for the honey-bee in which it is about 4-10-fold higher. The mass-action ratios for the reactions catalysed by phosphoglucoisomerase and adenylate kinase are very similar to the equilibrium constants for these reactions. Further, the variation in the mass-action ratios between muscles is small. It is concluded that these enzymes catalyse reactions close to equilibrium. However, the mass-action ratios for the reactions catalysed by phosphofructokinase and pyruvate kinase are much smaller than the equilibrium constants. The variation in the ratios between different muscles is large. It is concluded that these enzymes catalyse nonequilibrium reactions. Since the variation in the mass-action ratios for the reactions catalysed by the phosphagen kinases (i.e. creatine and arginine phosphokinases) is small, it is suggested that these reactions are close to equilibrium.

scholarly journals Antagonistic effects of hexose 1,6-bisphosphates and fructose 2,6-bisphosphate on the activity of 6-phosphofructokinase purified from honey-bee flight muscle

1986 ◽  
Vol 236 (3) ◽  
pp. 925-928 ◽  
Author(s):  
G Wegener ◽  
H Schmidt ◽  
A R Leech ◽  
E A Newsholme
Keyword(s):  
Honey Bee ◽  
Adenylate Kinase ◽  
Flight Muscle ◽  
Antagonistic Effects ◽  
Fructose 1,6 Bisphosphate ◽  
Low Activity

6-Phosphofructokinase purified from honey-bee flight muscle is inhibited by ATP and, unusually, by glucose 1,6-bisphosphate and fructose 1,6-bisphosphate. The inhibition by either of the bisphosphates is not relieved by AMP, but is relieved by fructose 6-phosphate and especially by fructose 2,6-bisphosphate. Lack of effect by AMP is consistent with a low activity of adenylate kinase in this muscle.

Studies on the energy metabolism in the isolated, perfused Rana ridibunda heart

1986 ◽  
Vol 64 (2) ◽  
pp. 485-489 ◽  
Author(s):  
A. Lazou ◽  
I. Beis
Keyword(s):  
Triosephosphate Isomerase ◽  
Adenine Nucleotides ◽  
Equilibrium Constants ◽  
Creatine Phosphate ◽  
Mass Action ◽  
Rana Ridibunda ◽  
Fructose Bisphosphate ◽  
Heart Work ◽  
Phosphofructokinase Activity ◽  
Tissue Contents

In the isolated, perfused Rana ridibunda heart, the concentrations of the metabolites were measured as a function of time, under increased heart work. The changes in tissue contents of adenine nucleotides were time dependent. ADP, AMP, and inorganic phosphate levels increased simultaneously, while ATP and creatine phosphate levels decreased. The tissue contents of hexose monophosphates and citrate decreased and contents of fructose bisphosphate, lactate, and pyruvate rose. A comparison of mass action ratios with apparent equilibrium constants for the glycolytic reactions indicated that phosphoglucose isomerase, aldolase, triosephosphate isomerase, and lactate dehydrogenase reactions are close to equilibrium, while phosphofructokinase is displaced from equilibrium. During increased heart work, changes in the tissue contents of adenine nucleotides and citrate appeared to play a role in the regulation of glycolysis at the level of phosphofructokinase activity. From the results, it appears that in amphibian heart, glycolysis seems to be similar to that of mammalian heart as far as control is concerned, in spite of its structural and functional differences.

scholarly journals Identification of novel DNA hypermethylation of the adenylate kinase 5 promoter in colorectal adenocarcinoma

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bokyung Ahn ◽  
Yang Seok Chae ◽  
Soo Kyung Lee ◽  
Moa Kim ◽  
Hyeon Soo Kim ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Cell Lines ◽  
Adenylate Kinase ◽  
Dna Methyltransferase ◽  
Colorectal Adenocarcinoma ◽  
Adenine Nucleotides ◽  
Inverse Correlation ◽  
Dna Hypermethylation ◽  
Normal Tissues ◽  
The Difference

AbstractAdenylate kinase 5 (AK5) belongs to the adenylate kinase family that catalyses reversible phosphate transfer between adenine nucleotides, and it is related to various energetic signalling mechanisms. However, the role of AK5 in colorectal cancer (CRC) has not been reported. In this study, AK5 was significantly hypermethylated in CRC compared to adjacent normal tissues (P < 0.0001) and normal tissues (P = 0.0015). Although the difference in mRNA expression was not statistically significant in all of them, the selected 49 cases of CRC tissues with AK5 hypermethylation with the cut off value of 40% showed a significant inverse correlation with mRNA expression (P = 0.0003). DNA methylation of AK5 promoter significantly decreased and AK5 expression recovered by 5-aza-2′-deoxycytidine, DNA methyltransferase inhibitor in CRC cell lines. In addition, AK5 promoter activity significantly decreased due to DNA methyltransferase, and it increased due to 5-aza. Moreover, AK5 regulated the phosphorylated AMPK and mTOR phosphorylation and inhibited the cell migration and cell invasion in CRC cell lines. Furthermore, low AK5 expression is associated with poor differentiation (P = 0.014). These results demonstrate that the AK5 promoter is frequently hypermethylated and induced methylation-mediated gene down-regulation. AK5 expression regulates AMPK/mTOR signalling and may be closely related to metastasis in colorectal adenocarcinoma.

A method for determining the periodicity of a troponin component in isolated insect flight muscle thin filaments by gold/Fab labelling

1992 ◽  
Vol 101 (3) ◽  
pp. 503-508
Author(s):  
R. Newman ◽  
G.W. Butcher ◽  
B. Bullard ◽  
K.R. Leonard
Keyword(s):  
Gold Particle ◽  
Colloidal Gold ◽  
Striated Muscle ◽  
Flight Muscle ◽  
Insect Flight ◽  
Insect Flight Muscle ◽  
Fab Fragment ◽  
Thin Filaments ◽  
Gold Particles ◽  
Almost All

Insect flight muscle has a large component (Tn-H) in the tropomyosin-troponin complex that is not present in vertebrate striated muscle thin filaments. Tn-H is shown by gold/Fab labelling to be present at regular intervals in insect flight muscle thin filaments. The Fab fragment of a monoclonal antibody to Tn-H was conjugated directly with colloidal gold and this probe used to label isolated thin filaments from the flight muscle of Lethocerus indicus (water bug). The distribution of gold particles seen in electron microscope images of negatively stained thin filaments was analysed to show that the probe bound to sites having a periodicity of approximately 40 nm, which is the expected value for the tropomyosin-troponin repeat. Conjugates of Fab with colloidal gold particles of 3 nm diameter labelled almost all sites. Conjugates with gold particles of 5 nm and 10 nm diameter labelled less efficiently (70% and 30%, respectively) but analysis of the distribution of inter-particle intervals among a number of filaments again gave the same fundamental spacing of 40 nm. The error in the measurements (standard deviation approximately +/− 4.2 for 5 nm gold/Fab) is less than earlier estimates for the size of the gold/Fab complex. Measurements on gold/Fab in negative stain suggest that the bound Fab contributes a shell about 2 nm in thickness around the gold particle. The radius of the probe (about 4.5 nm for 5 nm gold/Fab) would then be consistent with the value of error found. The size of the probe suggests that the gold particle binds to the side of the Fab molecule, rather close to the antibody combining site. The potential resolution of the technique may thus be better than originally expected.

X-ray titration of binding of β, γ-imido-ATP to myosin in insect flight muscle

Nature ◽  
1976 ◽  
Vol 262 (5569) ◽  
pp. 613-615 ◽  
Author(s):  
R. S. GOODY ◽  
J. BARRINGTON LEIGH ◽  
H. G. MANNHERZ ◽  
R. T. TREGEAR ◽  
G. ROSENBAUM
Keyword(s):  
Flight Muscle ◽  
Insect Flight ◽  
Insect Flight Muscle ◽  
X Ray
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