Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.17 (lysozyme)
 21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two forms of protein tyrosine phosphatases were partially purified from the musculo-cutaneous layer of Ascaris suum. A 50-55-kDa soluble form of the phosphatase cross-reacted with antisera raised against human PTP-1B and TC-PTP. Like the enzyme of human origin the phosphatase from Ascaris exhibited a preference for anionic substrates (tyrosine-phosphorylated carboxymethylated and maleylated lysozyme) and was inhibited by micromolar concentrations of vanadate, molybdate, Zn2+, heparin, and poly(Glu4Tyr). As revealed by immuno-cytochemistry, the phosphatase was mainly localized and appeared equally distributed in the cytoplasm, apart from the myofibrils, possibly in loose association with cytoskeletal elements. A second tyrosine phosphatase of 180 kDa molecular mass was mainly found in detergent extracts from a microsomal fraction. It showed no cross-reactivity with antisera raised against soluble mammalian phosphatases and dephosphorylated a basic substrate (Tyr-phosphorylated myelin basic protein). It was resistant to common inhibitors of mammalian tyrosine phosphatases except Zn2+ and thiol reagents.
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PMID:Protein phosphotyrosine phosphatases in Ascaris suum muscle. 881 64

Protein tyrosine phosphatases were analyzed in oocytes of Ascaris suum. Phosphatases dephosphorylating modified acidic lysozyme were present in high-molecular-weight form (M(r) > 600,000) and as a 50- to 55-kDa protein in the soluble fraction. The low-molecular-weight form of the phosphatase cross-reacted with an antiserum raised against human T-cell protein tyrosine phosphatase and was not distinguishable from the 50- to 55-kDa protein tyrosine phosphatase previously described in the muscular layer of the adult worms (B. Schmid et al. 1996, Molecular and Biochemical Parasitology 77, 183-192). The low-molecular-weight form was also present on immunoblots of high-molecular-weight protein tyrosine phosphatase preparations after denaturing electrophoresis. The same or a similar form of the tyrosine phosphatase was also found in detergent extracts from the pelletal fraction. In addition, another tyrosine phosphatase of 180 kDa molecular mass that dephosphorylated myelin basic protein was also found in extracts from the soluble compartment as well as in detergent extracts from the pelletal fraction. It showed no cross-reactivity with antisera raised against soluble mammalian phosphatases and was resistant to inhibition by vanadate. While the activities of the myelin basic protein-dephosphorylating protein phosphatase remained fairly constant during early development of the oocytes, the activity of the enzyme dephosphorylating modified lysozyme in the pelletal fraction decreased to less than 10% of the initial activity between days 3 and 28 of incubation. Immunocytochemical studies of unfertilized and developing Ascaris eggs revealed association of protein tyrosine kinase and protein tyrosine phosphatase with the egg shell, in addition to their presence in the neighborhood of mitochondria. The amount of enzyme changed with the stage of development. In the larval stage (21 days) protein tyrosine kinase had increased in the chitin layer of the shell and in the nuclei while the relative amount of tyrosine phosphatase decreased in accordance with the biochemical data.
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PMID:Ascaris suum: protein phosphotyrosine phosphatases in oocytes and developing stages. 953 68