Biomaterial Database

Detection of tripeptidyl peptidase I activity in living cells by fluorogenic substrates. 2006

Robert Steinfeld, and Jens C Fuhrmann, and Jutta Gärtner

Department of Pediatrics and Pediatric Neurology, University of Göttingen, Germany. rsteinfeld@med.uni-goettingen.de

Tripeptidyl peptidase I (TPP-I) is a lysosomal peptidase with unclear physiological function. TPP-I deficiency is associated with late-infantile neuronal ceroid lipofuscinosis (NCL), a fatal neurodegenerative disease of childhood that is characterized by loss of neurons and photoreceptor cells. We have developed two novel fluorogenic substrates, [Ala-Ala-Phe]2-rhodamine 110 and [Arg-Nle-Nle]2-rhodamine 110, that are cleaved by TPP-I in living cells. Fluorescence of liberated rhodamine 110 was detected by flow cytometry and was dependent on the level of TPP-I expression. Rhodamine-related fluorescence could be suppressed by preincubation with a specific inhibitor of TPP-I. When investigated by fluorescent confocal microscopy, rhodamine signals colocalized with lysosomal markers. Thus, cleavage of these rhodamide-derived substrates is a marker for mature enzymatically active TPP-I. In addition, TPP-I-induced cleavage of [Ala-Ala-Phe]2-rhodamine 110 could be visualized in primary neurons. We conclude that [Ala-Ala-Phe]2-rhodamine 110 and [Arg-Nle-Nle]2-rhodamine 110 are specific substrates for determining TPP-I activity and intracellular localization in living cells. Further, these substrates could be a valuable tool for studying the neuronal pathology underlying classical late-infantile NCL. This article contains online supplemental material at http://www.jhc.org. Please visit this article online to view these materials.

UI	MeSH Term	Description	Entries
D008214	Lymphocytes	White blood cells formed in the body's lymphoid tissue. The nucleus is round or ovoid with coarse, irregularly clumped chromatin while the cytoplasm is typically pale blue with azurophilic (if any) granules. Most lymphocytes can be classified as either T or B (with subpopulations of each), or NATURAL KILLER CELLS.	Lymphoid Cells,Cell, Lymphoid,Cells, Lymphoid,Lymphocyte,Lymphoid Cell
D008247	Lysosomes	A class of morphologically heterogeneous cytoplasmic particles in animal and plant tissues characterized by their content of hydrolytic enzymes and the structure-linked latency of these enzymes. The intracellular functions of lysosomes depend on their lytic potential. The single unit membrane of the lysosome acts as a barrier between the enzymes enclosed in the lysosome and the external substrate. The activity of the enzymes contained in lysosomes is limited or nil unless the vesicle in which they are enclosed is ruptured or undergoes MEMBRANE FUSION. (From Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed).	Autolysosome,Autolysosomes,Lysosome
D009842	Oligopeptides	Peptides composed of between two and twelve amino acids.	Oligopeptide
D010450	Endopeptidases	A subclass of PEPTIDE HYDROLASES that catalyze the internal cleavage of PEPTIDES or PROTEINS.	Endopeptidase,Peptide Peptidohydrolases
D004152	Dipeptidyl-Peptidases and Tripeptidyl-Peptidases	A subclass of exopeptidases that includes enzymes which cleave either two or three AMINO ACIDS from the end of a peptide chain.	Dipeptidyl Peptidase,Dipeptidyl Peptidases,Dipeptidylpeptide Hydrolase,Tripeptidyl-Peptidase,Dipeptidylpeptide Hydrolases,Tripeptidyl-Peptidases,Dipeptidyl Peptidases and Tripeptidyl Peptidases,Hydrolase, Dipeptidylpeptide,Peptidase, Dipeptidyl,Tripeptidyl Peptidase,Tripeptidyl Peptidases,Tripeptidyl-Peptidases and Dipeptidyl-Peptidases
D005347	Fibroblasts	Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules.	Fibroblast
D005456	Fluorescent Dyes	Chemicals that emit light after excitation by light. The wave length of the emitted light is usually longer than that of the incident light. Fluorochromes are substances that cause fluorescence in other substances, i.e., dyes used to mark or label other compounds with fluorescent tags.	Flourescent Agent,Fluorescent Dye,Fluorescent Probe,Fluorescent Probes,Fluorochrome,Fluorochromes,Fluorogenic Substrates,Fluorescence Agents,Fluorescent Agents,Fluorogenic Substrate,Agents, Fluorescence,Agents, Fluorescent,Dyes, Fluorescent,Probes, Fluorescent,Substrates, Fluorogenic
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000091346	Tripeptidyl-Peptidase 1	Lysosomal Serine proteases that release N-terminal tripeptide from a polypeptide and cleave peptides between hydrophobic residues. An enzyme that in humans encoded by the TPP1 gene. It is involved in the degradation of bone collagen. Mutations in this gene are associated with the CEROID LIPOFUSCINOSIS, NEURONAL, 2; and SPINOCEREBELLAR ATAXIA, AUTOSOMAL RECESSIVE CEROID LIPOFUSCINOSIS, NEURONAL, 2; AND SPINOCEREBELLAR ATAXIA, AUTOSOMAL RECESSIVE 7.	CLN2 Protein,TPP1 Protein,Tripeptidyl Aminopeptidase I,Tripeptidyl Peptidase I,Tripeptidyl Protease I,Tripeptidyl-Peptidase I,Peptidase I, Tripeptidyl,Protein, CLN2,Protein, TPP1
D000626	Aminopeptidases	A subclass of EXOPEPTIDASES that act on the free N terminus end of a polypeptide liberating a single amino acid residue. EC 3.4.11.	Aminopeptidase