scholarly journals Modification of the kinetic parameters of aldolase on binding to the actin-containing filaments of skeletal muscle

1977 ◽  
Vol 165 (1) ◽  
pp. 165-167 ◽  
Author(s):  
T P Walsh ◽  
F M Clarke ◽  
C J Masters

The kinetic parameters of fructose bisphosphate aldolase (EC 4.1.2.13) were shown to be modified on binding of the enzyme to the actin-containing filaments of skeletal muscle. Although binding to F-actin or F-actin-tropomyosin filaments results in relative minor changes in kinetic properties, binding to F-actin-tropomyosin-troponin filaments produces major alterations in the kinetic parameters, and, in addition, renders them Ca2+-sensitive. These observations may be relevant to an understanding of the function of this enzyme within the muscle fibre.

2021 ◽  
Vol 22 (11) ◽  
pp. 5598
Author(s):  
Sara Laine-Menéndez ◽  
Cristina Domínguez-González ◽  
Alberto Blázquez ◽  
Aitor Delmiro ◽  
Inés García-Consuegra ◽  
...  

Our goal was to analyze postmortem tissues of an adult patient with late-onset thymidine kinase 2 (TK2) deficiency who died of respiratory failure. Compared with control tissues, we found a low mtDNA content in the patient’s skeletal muscle, liver, kidney, small intestine, and particularly in the diaphragm, whereas heart and brain tissue showed normal mtDNA levels. mtDNA deletions were present in skeletal muscle and diaphragm. All tissues showed a low content of OXPHOS subunits, and this was especially evident in diaphragm, which also exhibited an abnormal protein profile, expression of non-muscular β-actin and loss of GAPDH and α-actin. MALDI-TOF/TOF mass spectrometry analysis demonstrated the loss of the enzyme fructose-bisphosphate aldolase, and enrichment for serum albumin in the patient’s diaphragm tissue. The TK2-deficient patient’s diaphragm showed a more profound loss of OXPHOS proteins, with lower levels of catalase, peroxiredoxin 6, cytosolic superoxide dismutase, p62 and the catalytic subunits of proteasome than diaphragms of ventilated controls. Strong overexpression of TK1 was observed in all tissues of the patient with diaphragm showing the highest levels. TK2 deficiency induces a more profound dysfunction of the diaphragm than of other tissues, which manifests as loss of OXPHOS and glycolytic proteins, sarcomeric components, antioxidants and overactivation of the TK1 salvage pathway that is not attributed to mechanical ventilation.


1988 ◽  
Vol 249 (3) ◽  
pp. 779-788 ◽  
Author(s):  
P S Freemont ◽  
B Dunbar ◽  
L A Fothergill-Gilmore

The complete amino acid sequence of human skeletal-muscle fructose-bisphosphate aldolase, comprising 363 residues, was determined. The sequence was deduced by automated sequencing of CNBr-cleavage, o-iodosobenzoic acid-cleavage, trypsin-digest and staphylococcal-proteinase-digest fragments. Comparison of the sequence with other class I aldolase sequences shows that the mammalian muscle isoenzyme is one of the most highly conserved enzymes known, with only about 2% of the residues changing per 100 million years. Non-mammalian aldolases appear to be evolving at the same rate as other glycolytic enzymes, with about 4% of the residues changing per 100 million years. Secondary-structure predictions are analysed in an accompanying paper [Sawyer, Fothergill-Gilmore & Freemont (1988) Biochem. J. 249, 789-793].


1985 ◽  
Vol 230 (1) ◽  
pp. 53-60 ◽  
Author(s):  
R Bais ◽  
H M James ◽  
A M Rofe ◽  
R A Conyers

Ketohexokinase (EC 2.7.1.3) was purified to homogeneity from human liver, and fructose-bisphosphate aldolase (EC 4.1.2.13) was partially purified from the same source. Ketohexokinase was shown, by column chromatography and polyacrylamide-gel electrophoresis, to be a dimer of Mr 75000. Inhibition studies with p-chloromercuribenzoate and N-ethylmaleimide indicate that ketohexokinase contains thiol groups, which are required for full activity. With D-xylulose as substrate, ketohexokinase and aldolase can catalyse a reaction sequence which forms glycolaldehyde, a known precursor of oxalate. The distribution of both enzymes in human tissues indicates that this reaction sequence occurs mainly in the liver, to a lesser extent in the kidney, and very little in heart, brain and muscle. The kinetic properties of ketohexokinase show that this enzyme can phosphorylate D-xylulose as readily as D-fructose, except that higher concentrations of D-xylulose are required. The kinetic properties of aldolase show that the enzyme has a higher affinity for D-xylulose 1-phosphate than for D-fructose 1-phosphate. These findings support a role for ketohexokinase and aldolase in the formation of glycolaldehyde. The effect of various metabolites on the activity of the two enzymes was tested to determine the conditions that favour the formation of glycolaldehyde from xylitol. The results indicate that few of these metabolites affect the activity of ketohexokinase, but that aldolase can be inhibited by several phosphorylated compounds. This work suggests that, although the formation of oxalate from xylitol is normally a minor pathway, under certain conditions of increased xylitol metabolism oxalate production can become significant and may result in oxalosis.


2021 ◽  
Vol 20 (1) ◽  
Author(s):  
David P. McBey ◽  
Michelle Dotzert ◽  
C. W. J. Melling

Abstract Background Intensive-insulin treatment (IIT) strategy for patients with type 1 diabetes mellitus (T1DM) has been associated with sedentary behaviour and the development of insulin resistance. Exercising patients with T1DM often utilize a conventional insulin treatment (CIT) strategy leading to increased insulin sensitivity through improved intramyocellular lipid (IMCL) content. It is unclear how these exercise-related metabolic adaptations in response to exercise training relate to individual fibre-type transitions, and whether these alterations are evident between different insulin strategies (CIT vs. IIT). Purpose: This study examined glycogen and fat content in skeletal muscle fibres of diabetic rats following exercise-training. Methods Male Sprague-Dawley rats were divided into four groups: Control-Sedentary, CIT- and IIT-treated diabetic sedentary, and CIT-exercised trained (aerobic/resistance; DARE). After 12 weeks, muscle-fibre lipids and glycogen were compared through immunohistochemical analysis. Results The primary findings were that both IIT and DARE led to significant increases in type I fibres when compared to CIT, while DARE led to significantly increased lipid content in type I fibres compared to IIT. Conclusions These findings indicate that alterations in lipid content with insulin treatment and DARE are primarily evident in type I fibres, suggesting that muscle lipotoxicity in type 1 diabetes is muscle fibre-type dependant.


2002 ◽  
Vol 365 (1) ◽  
pp. 249-258 ◽  
Author(s):  
Bernard KORZENIEWSKI ◽  
Jerzy A. ZOLADZ

Cytosolic pH in skeletal muscle may vary significantly because of proton production/consumption by creatine kinase and/or proton production by anaerobic glycolysis. A computer model of oxidative phosphorylation in intact skeletal muscle developed previously was used to study the kinetic effect of these variations on the oxidative phosphorylation system. Two kinds of influence were analysed: (i) via the change in pH across the inner mitochondrial membrane and (ii) via the shift in the equilibrium of the creatine kinase-catalysed reaction. Our simulations suggest that cytosolic pH has essentially no impact on the steady-state fluxes and most metabolite concentrations. On the other hand, rapid acidification/alkalization of cytosol causes a transient decrease/increase in the respiration rate. Furthermore, changes in pH seem to affect significantly the kinetic properties of transition between resting state and active state. An increase in pH brought about by proton consumption by creatine kinase at the onset of exercise lengthens the transition time. At intensive exercise levels this pH increase could lead to loss of the stability of the system, if not compensated by glycolytic H+ production. Thus our theoretical results stress the importance of processes/mechanisms that buffer/compensate for changes in cytosolic proton concentration. In particular, we suggest that the second main role of anaerobic glycolysis, apart from additional ATP supply, may be maintaining the stability of the system at intensive exercise.


2018 ◽  
Vol 12 ◽  
pp. 117793221880970 ◽  
Author(s):  
Arwa A Mohammed ◽  
Ayman MH ALnaby ◽  
Solima M Sabeel ◽  
Fagr M AbdElmarouf ◽  
Amina I Dirar ◽  
...  

Background: Mycetoma is a distinct body tissue destructive and neglected tropical disease. It is endemic in many tropical and subtropical countries. Mycetoma is caused by bacterial infections ( actinomycetoma) such as Streptomyces somaliensis and Nocardiae or true fungi ( eumycetoma) such as Madurella mycetomatis. To date, treatments fail to cure the infection and the available marketed drugs are expensive and toxic upon prolonged usage. Moreover, no vaccine was prepared yet against mycetoma. Aim: The aim of this study is to predict effective epitope-based vaccine against fructose-bisphosphate aldolase enzymes of M. mycetomatis using immunoinformatics approaches. Methods and materials: Fructose-bisphosphate aldolase of M. mycetomatis sequence was retrieved from NCBI. Different prediction tools were used to analyze the nominee’s epitopes in Immune Epitope Database for B-cell, T-cell MHC class II and class I. Then the proposed peptides were docked using Autodock 4.0 software program. Results and conclusions: The proposed and promising peptides KYLQ show a potent binding affinity to B-cell, FEYARKHAF with a very strong binding affinity to MHC I alleles and FFKEHGVPL that shows a very strong binding affinity to MHC II and MHC I alleles. This indicates a strong potential to formulate a new vaccine, especially with the peptide FFKEHGVPL which is likely to be the first proposed epitope-based vaccine against fructose-bisphosphate aldolase of M. mycetomatis. This study recommends an in vivo assessment for the most promising peptides especially FFKEHGVPL.


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