Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.5.1.52 (PNGase F)
 1,527 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Supernatants prepared from disrupted Coxiella burnetii possess acid phosphatase (ACP) activity that apparently accounts for the inhibition of the metabolic burst of formyl-Met-Leu-Phe(fMLP)-stimulated human neutrophils. Results are presented regarding purification and biochemical-biological characterization of the ACP. The highly purified enzyme, which exhibited an apparent M(r) of 91 K and optimal activity at pH 5.0, also inhibited neutrophils. The enzyme retained full activity at pH 4.5, 5.5, and 7.4, when incubated overnight at 0 degrees C and room temperature; at pH 5.5, it retained full activity after overnight incubation at 37 degrees C. Apparently, the enzyme contains asparagine-linked but not serine- or threonine-linked glycan residues since its treatment with N-glycosidase F (PNGase F) decreased its M(r) to 87 K and no changes were detected with O-glycosidase. The enzyme's capacity to hydrolyze phosphate from a number of phosphate-containing compounds was examined; five phosphocompounds were significantly hydrolyzed: 5'-CMP > fructose 1,6-diphosphate > tyrosine phosphate > 3'-AMP > 5'-AMP. The ACP also dephosphorylated (32)P-Raytide, a phosphotyrosine-containing peptide. Dephosphorylation of Raytide was inhibited by the following phosphatase inhibitors: sodium molybdate, potassium fluoride, sodium ortho-vanadate and D2, a heteropolymolybdate compound. These results indicate that C. burnetii ACP may play a role in disrupting tyrosine phosphorylation/dephosphorylation reactions associated with the signal transduction pathway culminating in the metabolic burst. Interestingly, Western blot analysis of ACP-inhibited neutrophils showed a marked increase in tyrosine phosphorylation of a 44 K protein as compared to uninhibited cells.
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PMID:Protein-tyrosine phosphatase activity of Coxiella burnetii that inhibits human neutrophils. 917 54

DPL2 (DPP10) found at chromosome 2q14.1 is a member of the dipeptidyl peptidase IV (DPIV) gene family. Here we characterize a novel short DPL2 isoform (DPL2-s), a 789-amino acid protein, that differs from the previously described long DPL2 isoform (DPL2-l) at the N-terminal cytoplasmic domain by 13 amino acids. The two DPL2 isoforms use alternate first exons. DPL2 mRNA was expressed mainly in the brain and pancreas. Multiple forms of recombinant DPL2-s protein were observed in 293T cells, having mobilities 96 kDa, 100 kDa, and approximately 250 kDa which may represent soluble DPL2, transmembrane DPL2 and multimeric DPL2 respectively. DPL2 is glycosylated as a band shift is observed following PNGase F deglycosylation. DPL2-s was expressed primarily on the cell surface of transfected 293T and PC12 cells. DPL2-s exhibits high sequence homology with other DPIV peptidases, but lacks a catalytic serine residue and lacks dipeptidyl peptidase activity. Substitutions of Gly(644)-->Ser, Lys(643)Gly(644)-->TrpSer, or Asp(561)Lys(643)Gly(644)-->TyrTrpSer in the catalytic motif did not confer dipeptidyl peptidase activity upon DPL2-s. Thus, although DPL2 is similar in structure and sequence to the other dipeptidyl peptidases, it lacks vital residues required to confer dipeptidyl peptidase activity and has instead evolved features that enable it to act as an important component of voltage-gated potassium channels.
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PMID:Molecular characterization of a novel dipeptidyl peptidase like 2-short form (DPL2-s) that is highly expressed in the brain and lacks dipeptidyl peptidase activity. 1629 Feb 53

Most membrane proteins are subject to posttranslational glycosylation, which influences protein function, folding, solubility, stability, and trafficking. This modification has been proposed to protect proteins from proteolysis and modify protein-protein interactions. Voltage-activated ion channels are heavily glycosylated, which can result in up to 30% of the mature molecular mass being contributed by glycans. Normally, the functional consequences of glycosylation are assessed by comparing the function of fully glycosylated proteins with those in which glycosylation sites have been mutated or by expressing proteins in model cells lacking glycosylation enzymes. Here, we study the functional consequences of deglycosylation by PNGase F within the same population of voltage-activated potassium (KV) channels. We find that removal of sugar moieties has a small, but direct, influence on the voltage-sensing properties and final opening-closing transition of Shaker KV channels. Yet, we observe that the interactions of various ligands with different domains of the protein are not affected by deglycosylation. These results imply that the sugar mass attached to the voltage sensor neither represents a cargo for the dynamics of this domain nor imposes obstacles to the access of interacting molecules.
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PMID:Deglycosylation of Shaker KV channels affects voltage sensing and the open-closed transition. 2988 May 80