Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.3.5 (5'-nucleotidase)
 3,167 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Galactosyltransferase (GalTF), sialyltransferase (SiaTF), fucosyltransferase (FucTF), 5'-nucleotidase (5'Nucl), and ADP-ribosyltransferase (RibTF) were determined in three subcellular fractions of tumor cells and adjacent control tissue from 20 patients with small primary infiltrating ductal adenocarcinomas of the breast. Viable, as pure tumor cell populations as possible were isolated, subfractionated, and their enzyme levels compared to those in the patients' sera. The activities in tumor cells of the three glycosyltransferases were two- to seven-fold higher, whereas 5'-Nucl and RibTF showed reduced activities when compared to adjacent noninvolved tissue. Serum GalTF and SiaTF were slightly elevated in early mammary carcinoma, whereas FucTF, 5'Nucl, and RibTF were decreased in comparison with a control group. The proposed tumor origin of circulating enzymes could not be confirmed. Surprisingly, only for RibTF could a correlation between tumor and serum activity be established; a weak correlation was found for SiaTF. However, no such relationship could be determined for GalTF, FucTF, or 5'Nucl. In conclusion, the enzyme profile of the tumor cell does not, except for RibTF, appear in the serum. Serum enzyme profiles, therefore, do not permit detection of the early stages of breast cancer. A high correlation between RibTF activity and cytosol estrogen and progesterone receptor levels has been determined in tumor cells, possibly indicating slower growing, more differentiated types of breast tumors.
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PMID:Enzyme activities in human breast tumor cells and sera. 299 19

We have shown recently that the bovine corpus luteum (CL) possesses specific luteal cell surface membrane binding sites for progesterone. We have now confirmed and extended these observations to compare the subcellular distribution of these binding sites in developing, mature and regressing CL. The median buoyant densities of luteal progesterone binding sites from early-, mid- and late-luteal phase CL were similar (though three of five density profiles for late-luteal phase CL showed association of steroid binding with a fraction with a lower density), and clearly resolved from nuclear, mitochondrial, lysosomal, peroxisomal, Golgi-endoplasmic reticulum-lysosomal and smooth endoplasmic reticulum markers. Specific binding of [3H]progesterone overlapped with the distributions of 5'-nucleotidase and luteinizing hormone receptor (luteal cell surface membrane markers) in both control and digitonin-treated gradients at all stages of the luteal phase. Since steroidogenic 'large luteal' and 'small luteal' cells of the CL are derived from the granulosa cells (GC) and theca of the preovulatory follicle, we also investigated whether similar receptors were present in the follicle, and describe for the first time specific membrane binding sites for progesterone in purified GC and thecal membranes from healthy bovine follicles of different sizes. Specific binding increased linearly with GC and thecal membrane protein concentration; however, it was detectable only when digitonin was included in the binding incubation. Binding sites were specific for progesterone; unlabelled progesterone competed for [3H]progesterone binding at low concentrations (IC50, 35 and 31 nmol/l) compared with testosterone (IC50, 905 and 870 nmol/l) and delta4-androstenedione (IC50, 1050 and 660 nmol/l) for GC and thecal receptors respectively. In contrast, oestradiol, oestrone, pregnenolone, cortisol, cholesterol, and a genomic progesterone receptor antagonist, RU486, competed poorly. Steroid binding was present in GC and thecal membranes of follicles of all sizes, but [3H]progesterone binding to GC membranes decreased significantly with increasing follicle size (P<0.02), perhaps indicating developmental regulation of GC membrane non-genomic progesterone receptors in the preovulatory bovine follicle. We suggest that these membrane steroid receptors may be involved in the autocrine/paracrine regulation of follicular function by progesterone.
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PMID:Bovine ovarian non-genomic progesterone binding sites: presence in follicular and luteal cell membranes. 983 59