Thiol compounds present in the cells can be divided into low molecular weight and protein . Protein thiol groups , derived from cysteine ​​, may be present as free thiols, disulfides and mixed disulfides in combination with a low molecular weight thiols : glutathione , cysteine ​​, homocysteine ​​, and ? - Glutamylocysteiną . Metabolic related reactions of thiols have an important role in platelet function , anucleate cells derived from megakaryocytes , and performing an important role in hemostasis .