Description
RP2-Tripeptidyl Peptidase-I is a rabbit polyclonal antibody made to the serine proteinase Tripeptidyl Peptidase-I. The antibody is made to a synthetic peptide based on the catalytic domain of human Tripeptidyl Peptidase-I. The antibody has been peptide-affinity purified, concentrated to 1.0 mg/ml, with the addition of 0.05% sodium azide as preservative and 50% glycerol as cryoprotectant.
Use
Tripeptidyl Peptidase-I, also known as TPP1, Tripeptidyl Aminopeptidase, Lysosomal Pepstatin Insensitive Protease, LCIP, Cell Growth-Inhibiting Gene 1 Protein and CLN2, is a lysosomal serine protease in the clan SB, family S53 in the MEROPS classification system. In the lysosome TPP-I is thought to be part of the battery of proteinases involved in protein breakdown, but the substrates of TPP-I remain poorly understood. Function perturbing mutations of TPP-I that decrease or eliminate TPP-I activity from cells have been implicated in classical late infantile neuronal ceroid lipofuscinosis (cLINCL), an autosomal recessive neurodegenerative disease of children. In cLINCL deposits of incompletely digested proteins accumulate in storage vesicles, leading to neuronal damage. Fibroblast cultures and brain tissue samples from cLINCL patients were found to lack TPP-I activity, and linkage analysis showed the link between the mutations and the disease. Introduction of TPP-I into brains of mice decreased neuronal damage in a model of cLINCL, and ablation of the TPP-I gene in mice leads to a cLINCL-like disorder. Intriguingly, TPP-I is found to be over expressed in colorectal cancer, although the mechanism of action is unclear. TPP-I is thought to autoactivate when the protein is packaged into the lysosome, in a pH dependant reaction. The cleaved propeptide domain is proposed to act as an inhibitor of TPP-I. Glycosylation of TPP-I is thought to modify the activity and stability of the enzyme, as well as add several kDa to the apparent mass on SDS PAGE gels. TPP-I is ubiquitously expressed, found in all tissues, and yet the precise functions and mechanisms are still poorly understood. The catalytic residues identity were difficult to determine, and it was unclear whether TPP-I was a serine proteinase or a Cysteine proteinase, but crystal structures indicate S475-E272-D276 as the active residues of the catalytic triad. The TPP-I sequence encodes a protein of 563 amino acids, with predicted mass of 61.2 kDa and pI of 6.0. A 572 residue form, with an additional 9 aminop acids at the aminoterminal end is also reported, with predicted mass of 62.3 kDa and pI of 6.2. A recommended starting concentration for Western blots is 1:1,000 when using colorimetric substrates such as BCIP/NBT, and 1:5,000 for chemiluminescent substrates. Higher concentrations of antibody may be needed for samples from more distantly related species. FOR RESEARCH USE ONLY; NOT FOR USE IN HUMANS.
Storage
The undiluted antibody solution is stable for approximately 12 months at -20C.
