Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0338671 (Steroids)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The susceptibility of the progesterone receptor, liganded either by the antiprogestin RU 486 or by the progestin ORG 2058, to chymotrypsin and trypsin degradation was investigated. The nuclear fraction was isolated from T47D cells previously exposed either to 0.1 microM [3H]RU 486 or to 0.1 microM [3H]ORG 2058. The proteolytic digestion was performed on the micrococcal nuclease hydrolysate. The molecular weights of the receptor fragments were calculated, in high salt buffer, from the sedimentation coefficients determined on a sucrose gradient and from the Stokes radii estimated by gel filtration on an Agarose A-0.5 m column. Micrococcal nuclease solubilized receptor forms with molecular weights of 80,000 and 75,000 for the antiprogestin- or progestin-liganded receptor, respectively. Chymotrypsin degraded these receptor forms to fragments with molecular weights of 23,000 either for the antiprogestin- or progestin-liganded receptor. Similar molecular weights of 23,000 were calculated for the progesterone receptor liganded either by the antiprogestin RU 436 or the progestin ORG 2058 following trypsin cleavage. We conclude that the degradation pattern of the progesterone receptor liganded either by the antiprogestin RU 486 or the progestin ORG 2058 following chymotrypsin or trypsin digestion seems to be similar.
Steroids 1990 Jun
PMID:Comparison of the physical properties of the nuclear progesterone receptor, bound to antiprogestin RU 486 or progestin ORG 2058, following limited proteolysis. 238 53

We have previously shown that the photoactive 4-azasteroid, [1,2 3H]N-4(benzylbenzoyl)-3-oxo-4-aza-4-methyl-5alpha-androst an-17beta-carboxamide is an effective probe of rat steroid 5alpha-reductase (isozyme-1) (5alphaR-1). In the current investigation, PEG-fractionated (6.5%) detergent-solubilized preparations containing 5alphaR-1 activity were ultraviolet (UV)-photolyzed with [3H]-4MABP and subsequently purified by 8.75% preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The fractions corresponding to the radioactive peak following the dye front were analyzed by 10% sodium dodecyl sulfate-polyacrylamide gel electrophoresis and showed the presence of a single, labeled, 26 KDa protein band, the apparent molecular weight of 5alphaR-1. TCA precipitation of the labeled fractions, followed by long-term digestion of the TCA pellet with chymotrypsin and high-performance liquid chromatography analysis, indicated that the majority of the radioactivity eluted with a peak retention time of 55-56 min. Rechromatography of this fraction using a modified gradient (elution 54-55 min), followed by sequence analysis, yielded a single N-terminal tetrapeptide with the sequence, -L-E-G-F-, corresponding to residues 15-18 of the 5alphaR-1 sequence. Site-directed mutagenesis studies indicated that mutant F18L showed an approximately 12-fold increase in the Km for testosterone, whereas the Km for reduced nicotinomide adenine dinucleotide phosphate remained virtually unaltered.
Steroids 1999 Mar
PMID:Analysis of the steroid binding domain of rat steroid 5alpha-reductase (isozyme-1): the steroid D-ring binding domain of 5alpha-reductase. 1040 Mar 80