Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:4.1.1.17 (ornithine decarboxylase)
 6,351 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The ventral and dorsal lobes of the rat prostate contain larger quantities of the aliphatic amines putrescine, spermidine and spermine and higher activities of the enzyme ornithine decarboxylase (ODC; EC 4.1.1.17) than other accessory sex glands. In contrast, the coagulating glands and the seminal vesicles contain only small quantities of the amines but the highest activities of the arginase (ARG; EC 3.5.3.1). Lineweaver-Burk plots indicated that the Km-values for ARG in the coagulating gland and ODC in the ventral prostate lobe were 20 mM and 0.2 mM, respectively. Castration decreased ODC and ARG activities to 3 and 50% of control levels, respectively, after 3 days, whilst the Km-values were unaffected. Daily administration of 3 mg dihydrotestosterone (DHT) prevented these castrational changes. Oestrogen treatment alone had no effect on the activities of the enzymes, but appeared to exert a synergistic effect with androgen on the ODC. Administration of androgen to intact rats for 7 days caused a dose-related alteration in the ratios of the various amines, particularly the spermine: putrescine ratio. A minor but significant decrease was also recorded in the activity of the ODC, which was mirrored by an increase in the levels of putrescine in the tissue. The data suggest that androgen control of the polyamine pathway is biphasic, first stimulatory and later inhibitory with lesions occurring at the ODC, possibly via short loop feedback of its product putrescine, but also at subsequent enzymic steps in spermidine and spermine biosynthesis.
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PMID:Androgen interaction with the polyamine system of the rat prostate. 368 84

The fruit of the Alcobaca landrace of tomato (Lycopersicon esculentum Mill.) have prolonged keeping qualities (determined by the allele a/c) and contain three times as much putrescine as the standard Rutgers variety (A/c) at the ripe stage (ARG Dibble, PJ Davies, MA Mutschler [1988] Plant Physiol 86: 338-340). Polyamine metabolism and biosynthesis were compared in fruit from Rutgers and Rutgers-a/c-a near isogenic line possessing the allele a/c, at four different stages of ripening. The levels of soluble polyamine conjugates as well as wall bound polyamines in the pericarp tissue and jelly were very low or nondetectable in both genotypes. The increase in putrescine content in a/c pericarp is not related to normal ripening as it occurred with time and whether or not the fruit ripened. Pericarp discs of both normal and a/c fruit showed a decrease in the metabolism of [1,4-(14)C]putrescine and [terminal labeled-(3)H]spermidine with ripening, but there were no significant differences between the two genotypes. The activity of ornithine decarboxylase was similar in the fruit pericarp of the two lines. Arginine decarboxylase activity decreased during ripening in Rutgers but decreased and rose again in Rutgers-a/c fruit, and as a result it was significantly higher in a/c fruit than in the normal fruit at the ripe stage. The elevated putrescine levels in a/c fruit appear, therefore, to be due to an increase in the activity of arginine decarboxylase.
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PMID:Polyamine Metabolism in Ripening Tomato Fruit : II. Polyamine Metabolism and Synthesis in Relation to Enhanced Putrescine Content and Storage Life of a/c Tomato Fruit. 1666 78