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)

Two receptor polypeptides have been identified in several studies by using cross-linking with interleukin 3 (IL-3). It has been suggested that proteolytic degradation of the larger polypeptide yields the lower molecular weight fragment, but there is little proof that this is the case. We have used several different approaches to characterize the polypeptides cross-linked in R6X or FDC-P1 cells. Several bifunctional cross-linkers of various sizes were tested to determine their effectiveness in cross-linking IL-3 to its receptor. The longer cross-linker gave the highest proportion of labeling of the low molecular weight band. Incubation in the absence of protease inhibitors caused a decrease in labeling of both cross-linked polypeptides, but no indication of a significant increase in the lower molecular weight band. Direct comparison of the two cross-linked polypeptides by V8 protease mapping showed no common peptides that might be expected if they were related molecules, except those derived from the iodinated IL-3. Digestion with N-glycanase resulted in a decrease in apparent molecular weight of 5000 in the larger polypeptide but a decrease of 15,000 in the smaller polypeptide. These results suggest that the 70-kd polypeptide identified by cross-linking of IL-3 represents a second binding chain of the receptor. By analogy with some of the other hemopoietin receptors, the 70- and 125-kd polypeptides may form a complex necessary for high affinity binding.
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PMID:Two polypeptides identified by interleukin 3 cross-linking represent distinct components of the interleukin 3 receptor. 156 67

Murine interleukin 5 (IL-5), a lymphokine produced by helper T cells, is involved in the regulation of growth and differentiation of B cells and other hematopoietic cells. The receptor for IL-5 has been identified as two cross-linked complexes on T88-M cells (a murine IL-5-dependent early B cell line). In this study the IL-5 receptor was directly characterized by utilizing an immobilized IL-5 column and a rat monoclonal antibody, designated H7, directed against the IL-5 receptor. H7 completely inhibited specific binding of 35S-labeled IL-5 to T88-M cells, and bound to IL-5-responsive cells, e.g. T88-M, BCL1-B20 (a chronic B-cell leukemia), and MOPC104E (a myeloma), whereas H7 did not bind to IL-5-non-responsive cells, e.g. X5563 (a myeloma), FDC-P1 (an IL-3-dependent line), and MTH (an IL-2-dependent CTLL). H7 could barely bind to T88-M cells in the presence of IL-5, and immunoprecipitated a major band with an Mr of approximately 60 kd from the extract of surface-radioiodinated T88-M cells. The precipitation of this 60 kd molecule was inhibited by the addition of IL-5. Analysis with immobilized IL-5 also revealed that a 60 kd molecule bound specifically to IL-5-coupled beads compared with control beads. Furthermore, no additional molecule with a higher Mr that was recognized by H7 appeared under non-reducing, compared with reducing, conditions. The 60 kd molecule recognized by H7 could be digested with N-glycanase to yield a protein band of approximately 55 kd.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Characterization of the murine interleukin 5 receptor by using a monoclonal antibody. 208 84