Tripeptidyl peptidases: enzymes that count.
Protein degradation is essential for the life and death of every cell. Proteins are broken down to their constitutive amino acids by a succession of peptidases, both in lysosomes and in the cytosol. Tripeptidyl-peptidases I and II are enzymes that can 'count to three' and release N-terminal tripeptides from oligopeptides generated by different endopeptidases. The tripeptides are then degraded by other exopeptidases to release amino acids and dipeptides. Mutations in tripeptidyl-peptidase I have recently been associated with a lysosomal storage disease, late infantile neuronal ceroid lipofuscinosis.
Tomkinson
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Dept of Biochemistry, Uppsala University, Biomedical Center, Box 576, SE-751 23 Uppsala, Sweden. Birgitta.Tomkinson@biokem.uu.se
D000626:Aminopeptidases; D003546:Cysteine Endopeptidases / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; D010450:Endopeptidases / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D016464:Lysosomal Storage Diseases / Q000378:metabolism; D008247:Lysosomes / Q000378:metabolism*; D009097:Multienzyme Complexes / Q000378:metabolism; D009472:Neuronal Ceroid-Lipofuscinoses / Q000378:metabolism; D010455:Peptides / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex; D011506:Proteins / Q000378:metabolism*; D012697:Serine Endopeptidases / Q000378:metabolism; D057057:Serine Proteases; D000091346:Tripeptidyl-Peptidase 1
D009097:Multienzyme Complexes; D010455:Peptides; D011506:Proteins; D000091346:Tripeptidyl-Peptidase 1; D010450:Endopeptidases; D057057:Serine Proteases; D000626:Aminopeptidases; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; C048001:tripeptidyl-peptidase 2; C000717267:TPP1 protein, human; D012697:Serine Endopeptidases; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex