Abundance of low molecular weight phosphotyrosine protein phosphatase in the nerve-ending fraction in the brain.
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.
Tanino
H
H
Department of Environmental Biochemistry, Kyoto Pharmaceutical University, Yamashinaku, Japan.
Yoshida
J
J
Yamamoto
R
R
Kobayashi
Y
Y
Shimohama
S
S
Fujimoto
S
S
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
D007527:Isoenzymes; D011518:Proto-Oncogene Proteins; C091645:Acp1 protein, rat; D017027:Protein Tyrosine Phosphatases