Preparation of hepatic stimulator substance from neonatal porcine liver by enzymatic hydrolysis and characterization of the liver proteins by LC-MS/MS bottom-up approach

Abstract

Hepatic stimulator substance (HSS) is prepared by the freeze-thaw method on a large scale, but it is time-consuming and inefficient. It is necessary to find a better method to improve the efficiency and yield of HSS. In this study, HSS was prepared by enzymatic hydrolysis of neonatal porcine liver with trypsin, papain, dispase, and alcalase. Relatively, dispase was found to be the best enzyme, based on the results of the degree of hydrolysis and MTT assay. Box-Behnken design-response surface method was used to optimize the conditions, which were as follows: enzyme (dispase) concentration, 4164 U/g; substrate concentration, 7% (w/v); hydrolysis time, 4.3 hr; temperature, 45 °C; and pH, 6.5. The degree of hydrolysis was (54.99 ± 1.57)%. Shotgun proteomics coupled with Gene Ontology (GO) analysis based on the PANTHER classification system was used to screen proteins from neonatal porcine liver. The results profiled the proteins into biological processes, molecular functions, and cellular components, thus laying a foundation for further studies on components involved in and mechanisms of liver regeneration. Overall, the results suggest that enzymatic hydrolysis might be a promising method for industrial application.

Keywords: Box–Behnken design-response surface method; Gene Ontology analysis; enzymatic hydrolysis; hepatic stimulator substance; nanoRPLC-Q Exactive Orbitrap mass spectrometer; neonatal porcine liver.