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)

In order to investigate the lectin-binding properties of the photoreceptor cGMP-gated channel, solubilized and purified channel protein was incubated with immobilized lectins followed by reconstitution of unbound proteins. Of the lectins tested, only concanavalin A (ConA) was able to specifically sediment channel activity. A 240-kDa protein, which copurifies with the 63-kDa channel protein but does not bind ConA, was also found to be sedimented by the ConA-affinity matrix, thereby implicating that it is associated with the channel complex. Treatment of the purified channel protein with the enzyme glycopeptidase F in the presence of the denaturing detergent sodium dodecyl sulfate resulted in a rapid reduction of the apparent molecular mass by 1.90 kDa, and the abolition of ConA-binding. No intermediate molecular weight species were observed, suggesting that the channel protein is N-glycosylated at one site only. Under nondenaturing conditions, the kinetics of deglycosylation were distinctly two-phased: 50-60% deglycosylation was achieved rapidly; however, prolonged incubation was required to arrive at complete deglycosylation. Reconstitution experiments showed that deglycosylation had no significant effect on the kinetics of channel protein activation by cGMP.
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PMID:Lectin binding and enzymatic deglycosylation of the cGMP-gated channel from bovine rod photoreceptors. 248 Mar 49

Photoaffinity labeling of atrial natriuretic factor (ANF) receptor in the plasma membranes from bovine aortic smooth muscle tissue using N alpha 5-(4-azidobenzoyl)-ANF-(5-28)- peptide labeled with 125I yielded a 130-kDa band. However, when smooth muscle cells from the same bovine aorta were placed in culture, the 130-kDa receptor quickly disappeared and a 60-kDa band began to appear at high density. After three passages, essentially no 130-kDa band was found and only the 60-kDa band was strongly labeled. The primary structures of the two receptor forms were compared by radiochemical peptide mapping after endoproteinase Glu-C digestion of photoaffinity-labeled and detergent-solubilized 130-kDa receptor from the aorta or the 60-kDa receptor from the cultured cells. The peptide mapping showed courses of digestion that were significantly different from each other, suggesting difference in their primary structures. The basal guanylate cyclase activity in the aortic membranes was 1.0 pmol cGMP produced.min-1.mg protein-1 at 37 degrees C using Mn(2+)-GTP as substrate. The corresponding activity in the membranes from the cultured cells was 20 fmol cGMP.min-1.mg protein-1. Binding studies gave a density of binding sites (Bmax) of 82 fmol/mg protein for the aortic membranes and 850 fmol/mg protein for the cultured cell membranes. These data suggest that the major form of ANF receptor in the cultured cells, namely the 60-kDa receptor, lacked guanylate cyclase activity. Northern blot analysis of poly(A)-RNA extracted form bovine thoracic aorta or adrenal cortex gave a single 3.6-kb band when 32P-labeled human A-type ANF receptor cDNA was used as a hybridization probe. However, no band was detected when C-receptor cDNA was used as a probe. In addition to the major 130-kDa band, extended SDS/PAGE revealed two additional faint bands with estimated molecular masses of 126 kDa and 135 kDa. Treatment with endoglycosidase H resulted in disappearance of the 126-kDa band and appearance of a 100-kDa band. The 130-kDa and 135-kDa bands were unchanged. Treatment by endoglycosidase F or glycopeptidase F reduced all three bands to a single 100-kDa band. These results suggest that the slight difference in mobility is due to different states of glycosylation.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Aortic smooth muscle contains guanylate-cyclase-coupled 130-kDa atrial natriuretic factor receptor as predominant receptor form. Spontaneous switching to 60-kDa C-receptor upon cell culturing. 790 Oct 5

C-type natriuretic peptide activation of guanylyl cyclase B (GC-B), also known as natriuretic peptide receptor B or NPR2, stimulates long bone growth, and missense mutations in GC-B cause dwarfism. Four such mutants (L658F, Y708C, R776W, and G959A) bound (125)I-C-type natriuretic peptide on the surface of cells but failed to synthesize cGMP in membrane GC assays. Immunofluorescence microscopy also indicated that the mutant receptors were on the cell surface. All mutant proteins were dephosphorylated and incompletely glycosylated, but dephosphorylation did not explain the inactivation because the mutations inactivated a "constitutively phosphorylated" enzyme. Tunicamycin inhibition of glycosylation in the endoplasmic reticulum or mutation of the Asn-24 glycosylation site decreased GC activity, but neither inhibition of glycosylation in the Golgi by N-acetylglucosaminyltransferase I gene inactivation nor PNGase F deglycosylation of fully processed GC-B reduced GC activity. We conclude that endoplasmic reticulum-mediated glycosylation is required for the formation of an active catalytic, but not ligand-binding domain, and that mutations that inhibit this process cause dwarfism.
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PMID:Catalytically Active Guanylyl Cyclase B Requires Endoplasmic Reticulum-mediated Glycosylation, and Mutations That Inhibit This Process Cause Dwarfism. 2447 69