Substrate specificity of the 3-methylmercaptopropionyl-CoA (DmdC1) dehydrogenase from Ruegeria pomeroyi DSS-3

Author(s):  
Tao Wang ◽  
Hao Shi ◽  
William B. Whitman

The acyl-CoA dehydrogenase family enzyme DmdC catalyzes the third step in the dimethylsulfoniopropionate (DMSP) demethylation pathway, the oxidation of 3-methylmercaptopropionyl-CoA (MMPA-CoA) to 3-methylthioacryloyl-CoA (MTA-CoA). To study its substrate specificity, the recombinant DmdC1 from Ruegeria pomeroyi was characterized. In addition to MMPA-CoA, the enzyme was highly active with short chain acyl-CoAs, with K m values for MMPA-CoA, butyryl-CoA, valeryl-CoA, caproyl-CoA, heptanoyl-CoA, caprylyl-CoA and isobutyryl-CoA of 36, 19, 7, 11, 14, 10, and 149 μM, respectively, and k cat values of 1.48, 0.40, 0.48, 0.73, 0.46, 0.23 and 0.01 sec −1 , respectively. Among these compounds, MMPA-CoA was the best substrate. The high affinity of DmdC1 for its substrate supports the model for kinetic regulation of the demethylation pathway. In contrast to DmdB, which catalyzes the formation of MMPA-CoA from MMPA, CoA and ATP, DmdC1 was not affected by physiological concentrations of potential effectors, such as DMSP, MMPA, ATP and ADP. Thus, compared to the other enzymes of the DMSP demethylation pathway, DmdC1 has only minimal adaptations for DMSP metabolism compared to other enzymes in the same family with similar substrates, supporting the hypothesis that it evolved relatively recently from a short chain acyl-CoA dehydrogenase involved in fatty acid oxidation. Importance We report the kinetic properties of DmdC1 from the model organism R. pomeroyi and close an important gap in the literature. While the crystal structure of this enzyme was recently solved and its mechanism of action described (X. Shao, H. Y. Cao, F. Zhao, M. Peng, et al., Mol Microbiol 111:1057-1073, 2019, https://doi.org/10.1111/mmi.14211 ), its substrate specificity and sensitivity to potential effectors was never examined. We show that DmdC1 has a high affinity for other short chain acyl-CoAs in addition to MMPA-CoA, which is the natural substrate in DMSP metabolism and is not affected by the potential effectors tested. This evidence supports the hypothesis that DmdC1 possesses few adaptations to DMSP metabolism and likely evolved relatively recently from a short chain acyl-CoA dehydrogenase involved in fatty acid oxidation. This work is important because it expands our understanding about the adaptation of marine bacteria to the increased availability of DMSP about 250 million years ago.

2019 ◽  
Vol 152 (Supplement_1) ◽  
pp. S9-S9
Author(s):  
Sheng Feng ◽  
Deborah Cooper ◽  
Lu Tan ◽  
Gail Meyers ◽  
Michael Bennett

Abstract Medium- and short-chain L-3-hydroxyacyl-coenzyme A dehydrogenase (M/SCHAD, SCHAD) deficiency is a mitochondrial fatty acid oxidation disorder (FAOD). This enzyme catalyzes the penultimate step in fatty acid oxidation, the NAD+ dependent conversion of L-3-hydroxyacyl-CoA to 3-ketoacyl-CoA for medium- and short-chain acyl-CoA intermediates (C4-C12). The clinical presentations of most patients are recurrent hypoglycemia associated with hyperinsulinism. We presented four infants with C4 acyl-carnitine elevation identified by newborn screening that also showed an unusual phenotype of congenital hypotonia and gross developmental delay. Enzymatic studies confirmed the disease. Sequencing analysis of all the HADH coding exons on the four patients revealed a homozygous variant of a novel change (c.908G>T, p.Gly303Val). Western blot analysis subsequently confirmed the lack of the SCHAD protein. In addition, there is another previously reported benign variant (c.257T>C) identified in three infants. Therefore, we postulate that the HADH variant (c.908G>T) is indeed pathogenic and associated with a severe phenotype as evidenced by the cases described herein. Population screening for the c.908G>T mutation suggests this mutation to be common among Puerto Ricans. We recommend that SCHAD deficiency is included as part of the differential diagnosis of all infants with congenital hypotonia.


1987 ◽  
Vol 244 (2) ◽  
pp. 387-391 ◽  
Author(s):  
N S Ross ◽  
C L Hoppel

Riboflavin deficiency in weanling rats causes a metabolic disorder characterized by failure to oxidize fatty acids. The disorder is similar to that seen in several human diseases, some of which are responsive to pharmacological doses of riboflavin. Previous analysis of the riboflavin-deficient rat has shown that the failure of fatty acid oxidation is due to a decrease in the activity of the acyl-CoA dehydrogenases of beta-oxidation. The activity of these flavoenzymes in liver rapidly decreases when a riboflavin-deficient diet is initiated. The objectives of these experiments were to analyse the effects of starvation on liver mitochondria isolated from the riboflavin-deficient rat. Our studies show that the decreased mitochondrial fatty acid oxidation induced by riboflavin deficiency is partially reversed by starvation. The extent of this reversal is proportional to the duration of starvation. The starvation-associated increase in fatty acid oxidation is mediated by an increase in the mitochondrial short-chain acyl-CoA dehydrogenase activity. The activity of this enzyme is increased such that the ratio of short-chain acyl-CoA dehydrogenase apoenzyme to holoenzyme does not change. We conclude that short-chain acyl-CoA dehydrogenase activity is limiting for fatty acid oxidation when its activity falls below a critical point. The increased mitochondrial specific activity of short-chain acyl-CoA dehydrogenase during starvation may result from an increased availability of flavin coenzyme or an increase in enzyme catalytic efficiency.


2020 ◽  
Vol 11 ◽  
Author(s):  
Alexandre Umpierrez Amaral ◽  
Moacir Wajner

Deficiencies of medium-chain acyl-CoA dehydrogenase, mitochondrial trifunctional protein, isolated long-chain 3-hydroxyacyl-CoA dehydrogenase, and very long-chain acyl-CoA dehydrogenase activities are considered the most frequent fatty acid oxidation defects (FAOD). They are biochemically characterized by the accumulation of medium-chain, long-chain hydroxyl, and long-chain fatty acids and derivatives, respectively, in tissues and biological fluids of the affected patients. Clinical manifestations commonly include hypoglycemia, cardiomyopathy, and recurrent rhabdomyolysis. Although the pathogenesis of these diseases is still poorly understood, energy deprivation secondary to blockage of fatty acid degradation seems to play an important role. However, recent evidence indicates that the predominant fatty acids accumulating in these disorders disrupt mitochondrial functions and are involved in their pathophysiology, possibly explaining the lactic acidosis, mitochondrial morphological alterations, and altered mitochondrial biochemical parameters found in tissues and cultured fibroblasts from some affected patients and also in animal models of these diseases. In this review, we will update the present knowledge on disturbances of mitochondrial bioenergetics, calcium homeostasis, uncoupling of oxidative phosphorylation, and mitochondrial permeability transition induction provoked by the major fatty acids accumulating in prevalent FAOD. It is emphasized that further in vivo studies carried out in tissues from affected patients and from animal genetic models of these disorders are necessary to confirm the present evidence mostly achieved from in vitro experiments.


1981 ◽  
Vol 196 (3) ◽  
pp. 803-809 ◽  
Author(s):  
F Bauché ◽  
D Sabourault ◽  
Y Giudicelli ◽  
J Nordmann ◽  
R Nordmann

To elucidate the mechanisms through which 2-mercaptoacetate administration inhibits fatty acid oxidation in the liver, the respiration rates induced by different substrates were studied polarographically in rat hepatic mitochondria isolated 3 h after 2-mercaptoacetate administration. Palmitoyl-L-carnitine oxidation was almost completely inhibited in either the absence or presence of malonate. Octanoate oxidation was also inhibited, and the intramitochondrial acyl-CoA content was markedly increased. The oxidation rate of pyruvate and 2-oxoglutarate on the one hand and of 3-hydroxybutyrate, succinate and glutamate on the other was either normal or only slightly decreased. In the presence of 2,4-dinitrophenol, the extent of the inhibition of palmitoyl-L-carnitine oxidation was unchanged. All these results are consistent with the hypothesis that the 2-mercaptoacetate inhibition of fatty acid oxidation is due to an inhibition of the beta-oxidation pathway itself. Finally, the mitochondrial defect responsible for this inhibition was shown to be an inhibition of palmitoyl-CoA dehydrogenase activity (EC 1.3.99.3).


PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0248942
Author(s):  
Jhih-Wei Huang ◽  
Ching-Hua Kuo ◽  
Han-Chun Kuo ◽  
Jin-Yuan Shih ◽  
Teng-Wen Tsai ◽  
...  

Peripheral neuropathy (PN) is a dose-limiting, painful adverse reaction associated with the use of paclitaxel. This common side effect was often partially attributed to the solvent used for solubilization of the highly hydrophobic drug substance. Therefore, the development of alternative formulations thrived, which included that of Abraxane® containing nanoparticle albumin-bound paclitaxel (nab-paclitaxel). However, studies demonstrated inconsistent conclusions regarding the mitigation of PN in comparison with the traditional formulation. The mass spectrometry-based cell metabolomics approach was used in the present study to explore the potentially associated mechanisms. Although no significant difference in the effects on cell viability was observed, fold changes in carnitine, several acylcarnitines and long-chain fatty acid(s) were significantly different between treatment groups in differentiated and undifferentiated SH-SY5Y cells. The most prominent difference observed was the significant increase of octanoylcarnitine in cells treated with solvent-based paclitaxel, which was found to be associated with significant decrease of medium-chain acyl-CoA dehydrogenase (MCAD). The findings suggested the potential role of altered fatty acid oxidation in the different neurotoxicity patterns observed, which may be a possible target for therapeutic interventions worth further investigation.


PEDIATRICS ◽  
1991 ◽  
Vol 87 (3) ◽  
pp. 328-333 ◽  
Author(s):  
William R. Treem ◽  
Jeffrey S. Hyams ◽  
Charles A. Stanley ◽  
Daniel E. Hale ◽  
Harris B. Leopold

Inherited defects in fatty acid oxidation, which have been described and diagnosed with increasing frequency in the last decade, are most commonly attributed to a deficiency in the activity of medium-chain acyl-CoA dehydrogenase. Few cases of the related enzyme defect of long-chain acyl-CoA dehydrogenase activity have been reported. An infant with documented long-chain acyl-CoA dehydrogenase deficiency is described with a detailed metabolic profile, long-term clinical follow-up, and response to treatment. This patient is compared with the seven previously published cases of this disorder in order to stress the unique features of the initial presentation, more subtle late manifestations of the disease, and clinical and biochemical differentiation from the more common medium-chain acyl-CoA dehydrogenase deficiency. This report stresses the enlarging spectrum of the clinical presentation and natural history of this defect in fatty acid oxidation.


Circulation ◽  
2002 ◽  
Vol 105 (3) ◽  
pp. 367-372 ◽  
Author(s):  
E. Douglas Lewandowski ◽  
Raymond K. Kudej ◽  
Lawrence T. White ◽  
J. Michael O’Donnell ◽  
Stephen F. Vatner

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