title: Abundance of low molecular weight phosphotyrosine protein phosphatase in the nerve-ending fraction in the brain.
abstract: The distribution of low molecular weight phosphotyrosine protein phosphatase (LMW-PTP) in subcellular fractions of rat brain tissue was investigated by immunoblotting analysis using anti-LMW-PTP antibody. The enzyme was detected in the 105000 g precipitate in addition to the supernatant of brain homogenate, even after the precipitate was extensively washed, and was abundant in the particulate fraction of nerve endings. Nerve ending LMW-PTP was effectively solubilized by 1% Triton X-100 or 1% deoxycholate, though the enzyme was solubilized by thorough sonication. Two forms of LMW-PTP, designated as LMW-PTP-I and -II, were separated from the nerve ending-rich fraction by chromatofocusing. Nerve endings PTP-I and -II were different in molecular weight, isoelectric point and susceptibility to activators and inhibitors. The properties of nerve endings LMW-PTP-I and -II were similar to those of cytosolic LMW-PTP-I and -II. The abundance of LMW-PTP in nerve endings as well as in the cytosol suggests that this enzyme plays an important role in synaptic function.
authors.affiliation: Department of Environmental Biochemistry, Kyoto Pharmaceutical University, Yamashinaku, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Tanino
authors.forename: J
authors.initials: J
authors.lastname: Yoshida
authors.forename: R
authors.initials: R
authors.lastname: Yamamoto
authors.forename: Y
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: S
authors.initials: S
authors.lastname: Shimohama
authors.forename: S
authors.initials: S
authors.lastname: Fujimoto
mesh_terms: D000818:Animals; D001921:Brain / Q000201:enzymology*; D003600:Cytosol / Q000201:enzymology; D007527:Isoenzymes / Q000737:chemistry / Q000378:metabolism*; D008970:Molecular Weight; D009411:Nerve Endings / Q000201:enzymology*; D017027:Protein Tyrosine Phosphatases / Q000737:chemistry / Q000378:metabolism*; D011518:Proto-Oncogene Proteins; D051381:Rats; D013379:Substrate Specificity
chemical_list: D007527:Isoenzymes; D011518:Proto-Oncogene Proteins; C091645:Acp1 protein, rat; D017027:Protein Tyrosine Phosphatases