Ribonuclease cleaves phosphodiester bonds between RNA nucleotides. It is a proteolytic enzyme that cleaves SNARE proteins in neurons. It binds the minor groove of DNA and cleaves the phosphodiester backbone. Plasmin proteolytically cleaves fibrin into fibrin degradation products that inhibit excessive fibrin formation. Activated caspase 8 cleaves these kinases, inhibiting necroptosis. It cleaves fibrinogen, similarly to thrombin. Carboxypeptidase cleaves peptide linkages during digestion of proteins. Neuraminidase also cleaves sialic acid residues from viral proteins, preventing aggregation of viruses. Furin cleaves these sections and activates the proteins. Chymotrypsin performs a hydrolysis reaction that cleaves after aromatic residues. Yeast tRNA cyclic phosphodiesterase cleaves the cyclic phosphodiester group to form a 2'-phosphorylated 3' end. Pepsin cleaves the 44 amino acids from pepsinogen to create more pepsin. After attachment, a protease of the host cell cleaves and activates the receptor-attached spike protein. RNase A cleaves specifically after pyrimidine nucleotides. Trypsin then cleaves proteins to smaller polypeptides.