s-protein samples in cold prepared vials in a laboratory, study of covid-19 infection in humans

acid acute amino anatomy atom biochemistry biomolecule biotechnology cancer cell chain chemical chemistry coagulation cold conceptual covid covid19 digestion disease enzyme enzymes formula health human humans illustration image infection insulin laboratory medical medicine metabolism model molecular molecule pepsin peptidase peptide peptides polymer polypeptide prepared protease proteasome protein proteolysis research respiratory samples science severe structure study syndrome system test trypsinlike vials