Tripeptidyl Peptidase 1 (TPP1) and Palmitoyl-Protein Thioesterase 1 (PPT1), 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. Approximately 10 mcg of protein is combined with substrate and incubated at 37 degrees C for 1 hour. 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 JLM, Winchester B, et al: A rapid fluorogenic palmitoyl-protein thioesterase assay: Pre and post natal diagnosis of INCL. Mol Genet Metab 1999;66:240-244)
The synthetic substrate for tripeptidyl peptidase 1 (TPP1) is Ala-Ala-Phe-7-amido-4-methylcoumarin. The leukocytes are homogenized. Approximately 5 mcg of protein is combined with substrate and incubated at 37 degrees C for 1 hour. 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;46:1005-1008)
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Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Specimens are processed Monday through Sunday.
Assay is performed Wednesday; 8 a.m.
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
WBC homogenate stored for 1 month
Performing Laboratory Location The location of the laboratory that performs the test