Succinylation is a post-translational modification of protein lysine residues with succinyl groups derived from succinyl CoA. Succinylation is considered a significant post-translational modification with the potential to impact protein function which is highly conserved across numerous species. The role of succinylation in the heart, especially in heart failure and myofibril mechanics, remains largely unexplored. Mechanical parameters were measured in myofibrils isolated from failing hearts of ischemic cardiomyopathy patients and non-failing donor controls. We employed mass spectrometry to quantify differential protein expression in myofibrils from failing ischemic cardiomyopathy hearts compared to non-failing hearts. In addition, we combined peptide enrichment by immunoprecipitation with liquid chromatography tandem mass spectrometry to quantitatively analyze succinylated lysine residues in these myofibrils. Several key parameters of sarcomeric mechanical interactions were altered in myofibrils isolated from failing ischemic cardiomyopathy hearts, including lower resting tension and a faster rate of activation. Of the 100 differentially expressed proteins, 46 showed increased expression in ischemic heart failure, while 54 demonstrated decreased expression in ischemic heart failure. Our quantitative succinylome analysis identified a total of 572 unique succinylated lysine sites located on 181 proteins, with 307 significantly changed succinylation events. We found that 297 succinyl-Lys demonstrated decreased succinylation on 104 proteins, while 10 residues demonstrated increased succinylation on 4 proteins. Investigating succinyl CoA generation, enzyme activity assays demonstrated that α-ketoglutarate dehydrogenase and succinate dehydrogenase activities were significantly decreased in ischemic heart failure. An activity assay for succinyl CoA synthetase demonstrated a significant increase in ischemic heart failure. Taken together, our findings support the hypothesis that succinyl CoA production is decreased and succinyl CoA turnover is increased in ischemic heart failure, potentially resulting in an overall decrease in the mitochondrial succinyl CoA pool, which may contribute to decreased myofibril protein succinylation in heart failure.

琥珀酰化是蛋白质赖氨酸残基的翻译后修饰，其具有衍生自琥珀酰CoA的琥珀酰基。琥珀酰化被认为是重要的翻译后修饰，具有影响蛋白质功能的潜力，该蛋白质在许多物种中高度保守。琥珀酸在心脏中的作用，尤其是在心力衰竭和肌原纤维力学中的作用，在很大程度上尚待探索。在从缺血性心肌病患者衰竭心脏和非衰竭供体对照中分离出的肌原纤维中测量机械参数。与未失败的心脏相比，我们采用质谱法来定量从失败的缺血性心肌病心脏中获得的肌原纤维中的差异蛋白表达。此外，我们将通过免疫沉淀进行的肽富集与液相色谱串联质谱相结合，以定量分析这些肌原纤维中的琥珀酰赖氨酸残基。从衰竭的缺血性心肌病心脏中分离出的肌原纤维中，肌节机械相互作用的几个关键参数发生了变化，包括较低的静息张力和较快的活化速率。在100种差异表达的蛋白质中，有46种在缺血性心力衰竭中表达增加，而有54种在缺血性心力衰竭中表达减少。我们的定量琥珀酰化酶分析发现，共有572个独特的琥珀酰赖氨酸位点位于181个蛋白质上，其中307个琥珀酰化事件发生了显着变化。我们发现297个琥珀酰赖氨酸在104种蛋白质上显示出减少的琥珀酰化作用，10个残基显示4种蛋白质的琥珀酰化增加。通过调查琥珀酰辅酶A的产生，酶活性测定表明，缺血性心力衰竭患者的α-酮戊二酸脱氢酶和琥珀酸脱氢酶活性显着降低。琥珀酰辅酶A合成酶的活性测定表明缺血性心力衰竭显着增加。综上所述，我们的发现支持以下假设：在缺血性心力衰竭中，琥珀酰CoA的产生减少而琥珀酰CoA的营业额增加，从而可能导致线粒体琥珀酰CoA池整体减少，这可能导致心力衰竭的肌原纤维蛋白琥珀酰化降低。酶活性测定表明，α-酮戊二酸脱氢酶和琥珀酸脱氢酶活性在缺血性心力衰竭中显着降低。琥珀酰辅酶A合成酶的活性测定表明缺血性心力衰竭显着增加。综上所述，我们的发现支持以下假设：在缺血性心力衰竭中，琥珀酰CoA的产生减少而琥珀酰CoA的营业额增加，从而可能导致线粒体琥珀酰CoA池整体减少，这可能导致心力衰竭的肌原纤维蛋白琥珀酰化降低。酶活性测定表明，α-酮戊二酸脱氢酶和琥珀酸脱氢酶活性在缺血性心力衰竭中显着降低。琥珀酰辅酶A合成酶的活性测定表明缺血性心力衰竭显着增加。综上所述，我们的发现支持以下假设：在缺血性心力衰竭中，琥珀酰CoA的产生减少而琥珀酰CoA的营业额增加，从而可能导致线粒体琥珀酰CoA池整体减少，这可能导致心力衰竭的肌原纤维蛋白琥珀酰化降低。