Tissue-dependent enzymatic control of N-acetyl-β-alanine by PTER

β-alanine is one of the most abundant β-amino acids in mammals and occupies a central position at the intersection of vitamin, dipeptide, and energy metabolism. In addition to dietary intake, β-alanine availability in mammalian tissues is shaped by endogenous biochemical pathways, including pyrimidine catabolism, transamination reactions, and dipeptide turnover, and contributes to the synthesis of carnosine-related dipeptides that support cellular buffering and stress responses. Beyond these established biochemical fates, β-alanine also gives rise to secondary metabolites, including N-acetyl-β-alanine. Although N-acetyl-β-alanine has been associated with metabolic disorders such as obesity and type II diabetes, its enzymatic regulation and physiological relevance have remained unknown. Here we show that the N-acetyltaurine hydrolase phosphotriesterase-related (PTER) also catalyzes the hydrolysis of N-acetyl-β-alanine. In vitro, recombinant PTER converts N-acetyl-β-alanine to free β-alanine at a substantially faster rate than N-acetyltaurine hydrolysis, whereas structurally similar metabolites, including N-acetyl-α-alanine and N-acetyl-γ-aminobutyric acid (N-acetyl-GABA), are not substrates. Genetic ablation of Pter in mice results in a tissue-dependent reduction in N-acetyl-β-alanine hydrolase activity and leads to unexpected tissue-dependent bidirectional dysregulation of N-acetyl-β-alanine levels. Levels of carnosine and other β-alanine pathway metabolites remain unaffected. In contrast, N-acetyltaurine exhibits uniform accumulation across tissues in Pter-deficient mice. Circulating levels of N-acetyl-β-alanine and N-acetyltaurine are regulated in a substrate availability-dependent manner, and pharmacological elevation of N-acetyl-β-alanine suppresses feeding and obesity, although less effectively than N-acetyltaurine in a diet-induced obesity mouse model. Together, these findings demonstrate that PTER exerts tissue-dependent control of N-acetyl-β-alanine abundance, thereby defining a previously unrecognized regulatory node in β-amino acid metabolism.