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Test Catalog

Test ID: TPPTL    
Tripeptidyl Peptidase 1 and Palmitoyl-Protein Thioesterase 1, Leukocytes

Method Description Describes how the test is performed and provides a method-specific reference

The synthetic substrate for palmitoyl-protein thioesterase 1 (PPT1) is 4-methylumbelliferyl-6-thiopalmitoyl-beta-glucoside. The leukocytes are homogenized and combined with protein and a substrate and incubated. The reaction is stopped with a glycine buffer. The fluorescence of the 4-methylumbelliferone product is read using a fluorescence plate reader and activity is calculated based on amount of product formed during the 1-hour incubation period.(van Diggelen OP, Keulemans JL, Winchester B, et al: A rapid fluorogenic palmitoyl-protein thioesterase assay: pre and postnatal diagnosis of INCL. Mol Genet Metab. 1999 Apr;66(4):240-244; Cowan T, Pasquali M: Laboratory investigations of inborn errors of metabolism. In: Sarafoglou K, Hoffman GF, Roth KS, eds. Pediatric Endocrinology and Inborn Errors of Metabolism. 2nd ed. McGraw-Hill; 2017:1139-1158)

 

The synthetic substrate for tripeptidyl peptidase 1 (TPP1) is Ala-Ala-Phe-7-amido-4-methylcoumarin. The leukocytes are homogenized and combined with protein and a substrate and incubated. The reaction is stopped with a glycine buffer. The fluorescence of the 7-amino-4-methylcoumarin product is read using a fluorescence plate reader and activity is calculated based on amount of product formed during the 1-hour incubation period.(Sohar I, Lin L, Lobel P: Enzyme-based diagnosis of classical late infantile neuronal ceroid lipofuscinosis: comparison of tripeptidyl peptidase I and pepstatin-insensitive protease assays. Clin Chem. 2000 Jul;46(7):1005-1008; Cowan T, Pasquali M: Laboratory investigations of inborn errors of metabolism. In: Sarafoglou K, Hoffman GF, Roth KS, eds. Pediatric Endocrinology and Inborn Errors of Metabolism. 2nd ed. McGraw-Hill; 2017:1139-1158)

PDF Report Indicates whether the report includes an additional document with charts, images or other enriched information

No

Day(s) Performed Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Preanalytical processing: Monday through Saturday.

Assay performed: Twice per month

Report Available The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

8 to 15 days

Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

WBC homogenate: 1 month

Performing Laboratory Location Indicates the location of the laboratory that performs the test

Rochester