Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.26.9 (ribonuclease)
 6,589 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A radiochemical method for the determination of the amino terminus on very small amounts (0.5-5 nmol) of protein is described. The high sensitivity of the method is achieved by using undiluted 1-fluoro-2,4-dinitro-[3,5-3H]benzene [( 3H]Dnp-F) as the labelling reagent under conditions in which a maximum amount of radioactive label is incorporated. Chemical homogeneity is achieved by reacting with excess unlabelled Dnp-F. High recovery is obtained by adding Dnp-albumin as carrier protein. A mixture of Dnp 14C-labelled amino acids is added prior to hydrolysis and identification of the amino terminus is made on the basis of the 3H/14C ratios of the separated Dnp-amino acids. The method was tested on insulin, pancreatic ribonuclease, and lysozyme which gave high 3H/14C ratios only in the expected amino-terminal amino acids. Application to multiple forms of poly(C)-avid ribonuclease gave only amino-terminal lysine. Two of four putative isozymes of 17 beta-hydroxysteroid dehydrogenase had serine as the amino terminus while the other two had aspartic acid or asparagine.
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PMID:A highly sensitive method for identification of amino termini of proteins: application to multiple forms of poly(C)-avid ribonuclease and 17 beta-hydroxysteroid dehydrogenase. 630 40

Human adipose tissue is known to have 17 beta-oxidoreductase activity, interconverting estrone (E1) and estradiol (E2), as well as androstenedione (A) and testosterone (T). We examined both the subcutaneous abdominal and intra-abdominal (visceral) adipose tissue of women for expression of types 1, 2, and 3 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) using ribonuclease (RNase) protection assay and RT-PCR/Southern blotting. Type 1 17 beta-HSD, which encodes the enzyme responsible for the conversion of E1 to E2 in the placenta and ovary, was expressed in the subcutaneous abdominal and intra-abdominal adipose tissue of women, but the messenger RNA transcripts were predominantly incompletely spliced and therefore unlikely to encode an active protein. A pseudogene for type 1 17 beta-HSD was also expressed in these tissues, but messenger RNA transcripts were again unspliced. Type 2 17 beta-HSD, which encodes an enzyme that can catalyze the conversion of T to A and E2 to E1, was expressed in both the subcutaneous abdominal and intra-abdominal adipose tissue of women. Type 3 17 beta-HSD was also expressed in adipose tissue from both sites studied. Type 3 17 beta-HSD encodes the enzyme that catalyzes the conversion of A to T in the testis and also converts E1 to E2. Together with aromatase, which is known to be expressed in adipose tissue, the expression of types 2 and 3 17 beta-HSD indicates that sex steroid production in the adipose tissue of women is a complex process. The association of visceral obesity with the development of insulin resistance and dyslipidaemia raises the question of the role of steroid production in adipose tissue in the pathogenesis of these disorders.
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PMID:Expression of types 1, 2, and 3 17 beta-hydroxysteroid dehydrogenase in subcutaneous abdominal and intra-abdominal adipose tissue of women. 943 39