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)

It has been well documented that rat AFP is separated into two discrete fractions electrophoretically and by ion exchange chromatography and it is generally accepted that the two forms of AFP, "Slow" and "Fast" variants, have different charges and molecular sizes. In this paper, the molecular basis of electrophoretic variants of rat alpha-fetoprotein (AFP) was studied. Carbohydrate-free rat AFP was electrophoretically homogeneous. Stepwise conversion of molecular sizes by deglycosylation with glycopeptidase F and the specific activities of the variants of which sugar chains were radiolabelled suggest that "Slow" and "Fast" variants have two and one sugar chains per molecule, respectively.
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PMID:[Electrophoretic variants of rat alpha-fetoprotein]. 172 Apr 12

Rat alpha-fetoprotein (RAFP) shows two discrete electrophoretic variants, slow and fast, with molecular weights of 72,500 and 69,500, respectively. To elucidate the structural basis of this heterogeneity, we developed the expression system of RAFP cDNA and its mutants with the use of cultured mouse fibroblasts and a retrovirus vector. This produced recombinant wild-type and three mutant proteins and has several advantages over the use of Escherichia coli or Saccharomyces cerevisiae. The mutants were designed to lack either one or both of the two possible glycosylation sites on RAFP. Electrophoretic analyses relating to the glycosylation states of the recombinant proteins as well as of natural RAFP produced by rat cells before and after digestion with glycopeptidase F indicated that the slow variant has carbohydrate units located at Asn-93 and Asn-229 and the fast one has one at Asn-229.
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PMID:Expression of rat alpha-fetoprotein cDNA and its mutants in cultured mouse fibroblasts and identification of glycosylation sites related to electrophoretic variants. 752 78

A high serum alpha-fetoprotein (AFP) level was found in a patient with endometrial adenocarcinoma of the uterus, which appeared to be hepatoid on histological examination. The AFP of this unusual patient was purified by immunoaffinity chromatography and characterized. The electrophoretic profiles on sodium dodecyl sulfate-polyacrylamide get electrophoresis both before and after glycopeptidase F treatment were indistinguishable from those of a hepatoma AFP. This indicates that the patient's AFP was also composed of a single polypeptide chain of Mr 67,000 and an N-linked sugar chain of Mr 3,000. Amino acid sequence analyses of this AFP, and of AFP from hepatoma and umbilical cord serum indicated that the N-terminal sequences were essentially the same. The sequence, Arg-Thr-Leu-His-Arg-Asn-Glu-Tyr-Gly-Ile, was slightly different from previous reports, but matched that deduced from the cDNA sequence. AFP isoforms due to microheterogeneity of the sugar chain were analyzed by lectin affinity electrophoresis using a series of lectins. The AFP isoform profiles were distinct from those of proteins derived from cord serum, hepatoma, yolk sac tumor and gastric cancer. The reverse-transcription of RNA from the tumor tissue followed by a polymerase chain reaction using primers with AFP-specific sequences gave a product of the size and nucleotide sequence expected for AFP. mRNAs possessing the requisite sequences for albumin and transferrin syntheses were also detected in the tumor. The expression of these hepatocyte-specific proteins supported the hepatoid nature of this tumor.
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PMID:Biochemical characterization of alpha-fetoprotein and other serum proteins produced by a uterine endometrial adenocarcinoma. 876 25