Skip to main content
. 2021 May 17;12:612888. doi: 10.3389/fendo.2021.612888

Figure 1.

Figure 1

Enzymatic profile for skeletal muscle mitochondria in the IUGR fetus. The schematic outlines major mitochondrial enzymes and their processes in the tricarboxylic acid (TCA) cycle and in the electron transport chain (ETC). Lower abundances (red text) and greater abundances (blue text) for IUGR mitochondria are indicated, whereas enzymes that are not different from control mitochondria are in black text. Proposed decreased metabolic fluxes in IUGR mitochondria are shown with red (lower) and blue (higher). Here, fluxes of pyruvate, amino acids, and fatty acids are all thought to be lower in the IUGR skeletal muscle due to lower enzyme expression involved in each pathway. Initial pyruvate flux is thought to be hindered by higher MPC2 expression and is believed to be further slowed by lower expressions of IDH, OGDH, and SUCLA2. Because these enzymes are also innately involved in amino acid flux into the TCA cycle, amino acid degradation is also believed to be lower in IUGR skeletal muscle mitochondria. Moreover, higher NDUFA4L2 expression in IUGR skeletal muscle mitochondria is believed to slow electron flux leading to a) lower reactive oxygen species (ROS) production b) lower oxygen consumption rates c) lower NADH oxidation. ACO1/2†, aconitate hydratase 1/2 (121); CACT†, carnitine–acylcarnitine carrier (121); CPT2†, carnitine palmitoyltransferase 1,2 (121); CS†, citrate synthase (121); FH†, fumarate hydratase (121); GOT1, Glutamic-oxaloacetic transaminase 1; GOT2†, glutamic-oxaloacetic transaminase 2 (121); IDH†, isocitrate dehydrogenase (121); LDHA‡, lactate dehydrogenase A (121); LDHB†, lactate dehydrogenase B (121); MDH1, malate dehydrogenase 1 (121); MDH2†, malate dehydrogenase 2 (121); MPC2†, mitochondrial pyruvate carrier 2 (121); NDUFA4L2†, NDUFA4 mitochondrial complex associated like 2 (121); OGDH†, oxoglutarate dehydrogenase (121); PC#, pyruvate carboxylase (121, 124); PDH●†, pyruvate dehydrogenase (121); PDK1-4#, pyruvate dehydrogenase kinases 1-4 (85, 121); SDHA–D†, succinate dehydrogenase A–D (121); SUCLA2†, succinate-CoA ligase ADP-forming subunit β (121). †denotes protein data, ‡denotes mRNA data, #denotes protein and mRNA data. ●denotes activity data. The image was created in BioRender.com.