LDHB

Lactate dehydrogenase B (LDHB) catalyzes the reversible conversion of lactate to pyruvate, maintaining NAD+/NADH homeostasis in glycolytic metabolism[1]. Mechanistically, LDHB activity supports autophagy in cancer cells, linking metabolic flux to cell survival under nutrient stress[2]. LDHB is distinct from LDHA in its pH-dependent kinetics, showing lower NADH affinity and a greater sensitivity to inorganic phosphate activation, indicating isoform-specific regulatory features[1]. Phylogenetic analyses indicate that LDHB arose from a single ancestral locus prior to the divergence of cartilaginous and bony fishes, highlighting its evolutionary conservation in heart-predominant tissues[3]. In disease models, elevated LDHB expression correlates with serum LDH levels in cardiac tissue and predicts metabolic adaptation in tumors, establishing its relevance as a biomarker and therapeutic target[4][5]. Selective LDHB inhibitors, including peptide-based and pyrazole derivatives, demonstrate isoform-specific inhibition, enabling mechanistic studies of LDHB function in vitro and in vivo[6][7][8]. For experimental applications, these inhibitors allow differentiation of LDHB-mediated metabolic flux from LDHA-driven glycolysis, supporting studies in oncology, cardiology, and microbial metabolism[1][8]. Compared with LDHA, LDHB exhibits narrower substrate specificity and distinct activation properties, emphasizing its unique role in tissue-specific energy metabolism[1].
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