||Human scrum albumin (HSA) is the most abundant protein in human plasma and plays versatile biological role. HSA has been widely used to treat several diseases and develop biocompatible biomaterials for biomedical applications. However, pharmaceutical-grade HSA (p-HSA) showed the altered oxidative and ligand-binding properties compare to native HSA. To investigate the influences of the manufacturing process on the molecular state of HSA, we determined the first crystal structure of p-HSA using the commercial HSA solution without any defatting step and further purification and carried out mass spectrometry to identify bound ligands. The crystal structure of p-HSA revealed that medium- and long-chain fatty adds and tryptophan are bound top-HSA and one free cystene is oxidized to cysteine-sulfenic acid. The mass spectra of p-HSA also confirmed the existence of fatty adds and tryptophan in p-HSA Our results enhance understanding of the molecular state of p-HSA and can be utilized to produce p-HSA solutions and HSA-based biomaterials that has a higher biorelevance. (C) 2020 Elsevier B.V. All rights reserved.