title: Downregulation of specific protein carboxylmethyltransferase immunoreactivity in human endometrial carcinoma.
abstract: Protein carboxylmethyltransferases (PCMT), enzymes that methylate free carboxyl groups of proteins, are involved in functional modification of various proteins including those of age-damaged proteins and the oncogenic ras proteins. Several species of PCMT are associated with these modifications. By using western blot analysis and specific antibodies raised against one type of PCMT, a 30-kilodalton (KD) cytosolic enzyme from Torpedo electric organ was identified in human erythrocytes and endometrium. The high specificity of the antibodies made it possible to compare levels of immunoreactive 30-KD PCMT protein in normal human endometria and endometrial carcinomas. Assays done on samples from 23 patients indicated the average levels of immunoreactive 30-KD PCMT in endometrial carcinomas was one fifth that of normal endometrium. The sensitivity of the assay was 83%, and its specificity was 90%. These results suggest that levels and activity of the 30-KD PCMT may be downregulated to maintain the phenotypic expression of the endometrial carcinoma. These assays may be used to assist in the detection of endometrial carcinomas.
authors.affiliation: Department of Biochemistry, George S. Wise Faculty of Life Sciences, Tel Aviv University, Israel.
authors.forename: R
authors.initials: R
authors.lastname: Solomon
authors.forename: G
authors.initials: G
authors.lastname: Ben Baruch
authors.forename: J
authors.initials: J
authors.lastname: Menczer
authors.forename: Y
authors.initials: Y
authors.lastname: Kloog
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015153:Blotting, Western; D002277:Carcinoma / Q000201:enzymology*; D015536:Down-Regulation / Q000502:physiology*; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008970:Molecular Weight; D011497:Protein O-Methyltransferase / Q000737:chemistry / Q000378:metabolism*; D012016:Reference Values; D012680:Sensitivity and Specificity; D014594:Uterine Neoplasms / Q000201:enzymology*; D014599:Uterus / Q000201:enzymology*
chemical_list: D011497:Protein O-Methyltransferase