<p>Silent information regulator 5 (SIRT5), serving as an important regulator of post-translational modification, regulates several cellular key metabolic enzymes. However, the role of SIRT5 in pancreatic beta cell function and regulation remains unclear at present. In previous study, we noticed that the expression level of SIRT5 altered significantly in pancreas from diabetic animals comparing with normal animals. Moreover, its expression level fluctuated in accordance with several crucial mitochondrial apoptotic factors. Thus, we speculate that SIRT5 might contribute to the protection of pancreatic beta cell against excess nutrients burden. </p><p>　Cell lines as well as islets from multiple origins were utilized. We established High palmitate and glucose induced cell apoptosis model. Afterwards, TUNEL-DAPI double staining, Hoechst-PI double staining and real-time cell growth monitor system were used to identify whether SIRT5 participated in the regulation of cell apoptosis. Then its influence on pancreatic beta cell function was detected through glucose stimulated insulin secretion and mitochondria membrane potential assay, while relevant genes and proteins were also examined to explore its molecular mechanism. Moreover, luciferase reporter gene, and endoplasmic reticulum stress relevant genes and protein factors were also examined for the effects of SIRT5. Finally, coimmunoprecipitation and luciferase reporter gene assay were utilized to assess the possible connection between SIRT5 and a certain antiapoptosis factor as well as its effects on beta cell function and survival.</p><p>　The results showed that SIRT5 could significantly diminish the apoptotic cell quantity without causing over proliferation. Besides, under excess glucose and fatty acid status, insulin secretion was also moderately improved, indicating a protective role of SIRT5. This effect was also displayed in various cell models, including rat pancreatic beta cell line INS1, mouse pancreatic beta cell line MIN6 and NIT1. Respectively, SIRT5 silencing led to lower responsiveness for glucose stimulation. There are parts of the molecular mechanisms that could explain the protective role of SIRT5, via direct inhibition of Caspase family and suppressed endoplasmic reticulum stress. </p><p>　Our study enclosed the relationship between SIRT5 and beta cell protection and relevant regulation mechanism as well as the molecular mechanism of beta cell injury.</p>