Lactate Dehydrogenase-B Oxidation and Inhibition by Singlet Oxygen and Hypochlorous Acid
Alterations in cellular energy metabolism are a hallmark of cancer and lactate dehydrogenase (LDH) enzymes are overexpressed in many cancers regardless of sufficient oxygen and functional mitochondria. Further, L-lactate plays signaling roles in multiple cell types. We evaluated the effect of single...
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2024-11-01
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| author | Lisa M. Landino Emily E. Lessard |
| author_facet | Lisa M. Landino Emily E. Lessard |
| author_sort | Lisa M. Landino |
| collection | DOAJ |
| description | Alterations in cellular energy metabolism are a hallmark of cancer and lactate dehydrogenase (LDH) enzymes are overexpressed in many cancers regardless of sufficient oxygen and functional mitochondria. Further, L-lactate plays signaling roles in multiple cell types. We evaluated the effect of singlet oxygen and hypochlorous acid (HOCl) on pig heart LDH-B, which shares 97% homology with human LDH-B. Singlet oxygen was generated photochemically using methylene blue or the chlorophyll metabolites, pheophorbide A and chlorin e6. Singlet oxygen induced protein crosslinks observed by SDS-PAGE under reducing conditions and inhibited LDH-B activity. Ascorbate, hydrocaffeic acid, glutathione and sodium azide were employed as singlet oxygen scavengers and shown to protect LDH-B. Using fluorescein-modified maleimide, no changes in cysteine availability as a result of singlet oxygen damage were observed. This was in contrast to HOCl, which induced the formation of disulfides between LDH-B subunits, thereby decreasing LDH-B labeling with fluorescein. HOCl oxidation inhibited LDH-B activity; however, disulfide reduction did not restore it. LDH-B cysteines were resistant to millimolar H<sub>2</sub>O<sub>2</sub>, chloramines and Angeli’s salt. In the absence of pyruvate, LDH-B enhanced NADH oxidation in a chain reaction initiated by singlet oxygen that resulted in H<sub>2</sub>O<sub>2</sub> formation. Once damaged by either singlet oxygen or HOCl, NADH oxidation by LDH-B was impaired. |
| format | Article |
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| institution | DOAJ |
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| language | English |
| publishDate | 2024-11-01 |
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| spelling | doaj-art-4541f173edc74de2abf0a4e1867011a32025-08-20T02:57:20ZengMDPI AGOxygen2673-98012024-11-014443244810.3390/oxygen4040027Lactate Dehydrogenase-B Oxidation and Inhibition by Singlet Oxygen and Hypochlorous AcidLisa M. Landino0Emily E. Lessard1Department of Chemistry, College of William & Mary, Williamsburg, VA 23187-8795, USADepartment of Chemistry, College of William & Mary, Williamsburg, VA 23187-8795, USAAlterations in cellular energy metabolism are a hallmark of cancer and lactate dehydrogenase (LDH) enzymes are overexpressed in many cancers regardless of sufficient oxygen and functional mitochondria. Further, L-lactate plays signaling roles in multiple cell types. We evaluated the effect of singlet oxygen and hypochlorous acid (HOCl) on pig heart LDH-B, which shares 97% homology with human LDH-B. Singlet oxygen was generated photochemically using methylene blue or the chlorophyll metabolites, pheophorbide A and chlorin e6. Singlet oxygen induced protein crosslinks observed by SDS-PAGE under reducing conditions and inhibited LDH-B activity. Ascorbate, hydrocaffeic acid, glutathione and sodium azide were employed as singlet oxygen scavengers and shown to protect LDH-B. Using fluorescein-modified maleimide, no changes in cysteine availability as a result of singlet oxygen damage were observed. This was in contrast to HOCl, which induced the formation of disulfides between LDH-B subunits, thereby decreasing LDH-B labeling with fluorescein. HOCl oxidation inhibited LDH-B activity; however, disulfide reduction did not restore it. LDH-B cysteines were resistant to millimolar H<sub>2</sub>O<sub>2</sub>, chloramines and Angeli’s salt. In the absence of pyruvate, LDH-B enhanced NADH oxidation in a chain reaction initiated by singlet oxygen that resulted in H<sub>2</sub>O<sub>2</sub> formation. Once damaged by either singlet oxygen or HOCl, NADH oxidation by LDH-B was impaired.https://www.mdpi.com/2673-9801/4/4/27lactate dehydrogenasesinglet oxygenhypochlorous acidcysteine oxidationreactive oxygen speciesdisulfide |
| spellingShingle | Lisa M. Landino Emily E. Lessard Lactate Dehydrogenase-B Oxidation and Inhibition by Singlet Oxygen and Hypochlorous Acid Oxygen lactate dehydrogenase singlet oxygen hypochlorous acid cysteine oxidation reactive oxygen species disulfide |
| title | Lactate Dehydrogenase-B Oxidation and Inhibition by Singlet Oxygen and Hypochlorous Acid |
| title_full | Lactate Dehydrogenase-B Oxidation and Inhibition by Singlet Oxygen and Hypochlorous Acid |
| title_fullStr | Lactate Dehydrogenase-B Oxidation and Inhibition by Singlet Oxygen and Hypochlorous Acid |
| title_full_unstemmed | Lactate Dehydrogenase-B Oxidation and Inhibition by Singlet Oxygen and Hypochlorous Acid |
| title_short | Lactate Dehydrogenase-B Oxidation and Inhibition by Singlet Oxygen and Hypochlorous Acid |
| title_sort | lactate dehydrogenase b oxidation and inhibition by singlet oxygen and hypochlorous acid |
| topic | lactate dehydrogenase singlet oxygen hypochlorous acid cysteine oxidation reactive oxygen species disulfide |
| url | https://www.mdpi.com/2673-9801/4/4/27 |
| work_keys_str_mv | AT lisamlandino lactatedehydrogenaseboxidationandinhibitionbysingletoxygenandhypochlorousacid AT emilyelessard lactatedehydrogenaseboxidationandinhibitionbysingletoxygenandhypochlorousacid |