<prompt> Conversion of fibrinogen to fibrin is byProthrombinFactor XIIIThrombinKallikrein  <response>: Thrombin conves soluble fibrinogen to fibrin monomer Prothrombin is the precursor or thrombin Factor XIII is fibrin stabilization factor Kallikrein activates factor XII Ref: Medical Physiology Indu Khurana 2015 edition page No:154 