Genetic control of tyramine oxidase, which is involved in derepressed synthesis of arylsulfatase in Klebsiella aerogenes

Abstract

Mutants of Klebsiella aerogenes with three types of mutations affecting regulation of tyramine oxidase were isolated by a simple selection method. In the first type, the mutation (tynP) was closely linked to the structural gene for tyramine oxidase tynA). The order of mutation sites was atsA-tynP-tynA. In the second type, the mutation that relieves catabolite repression of the syntheses of several catabolite repression-sensitive enzymes are not linked to the tyn gene by P1 transduction. These strains contained high levels of cyclic adenosine 5'-monophosphate when grown on glucose. The third type of mutation, in which tyramine oxidase was synthesized constitutively, was shown by genetic analysis to involve mutations of tynP and tynR. The tynR gene was not linked to tynA. Results using the constitutive mutants showed that the constitutive expression of the tynA gene resulted in depression of arylsulfatase synthesis in the absence of tyramine.

Regulation of derepressed synthesis of arylsulfatase by tyramine oxidase in Salmonella typhimurium

“…The amount of tyramine taken up at 30°C in 30 8 was determined as described in the text. dase by the growth method described previously (14). Wild-type strain LT2 grew very slowly (doubling time, about 14 h) on minimal medium with tyramine as the sole source of nitrogen when glucose was used as the carbon source (GT medium).…”

“…In this paper, we show that arylsulfatase from S. typhimurium LT2 differs greatly from the enzyme of K. aerogenes (17) and Serratia marcescens (13) in its Km and V.. values. Comparative studies on the regulation of the syntheses of tyramine oxidase and arylsulfatase and genetic studies on mutant strains, such as tynA, tynP, or tynP tynR, in K. aerogenes led us to the interesting conclusion that the apparent level of derepressed synthesis of arylsulfatase by tyramine under conditions of catabolite and ammonium repression is just a reflection of the regulation pattem of tyramine oxidase synthesis (9,14,16). The experiments reported here clearly show that the regulation of arylsulfatase synthesis in S. typhimurium is similar to that in K. aerogenes, except for the effect of methionine, although this idea has been strongly challenged by others (7).…”

“…Arylsulfatase synthesis in Klebsiella aerogenes is repressed by a repressor molecule (atsR) that has been activated by a corepressor, such as inorganic sulfate, cysteine, or related compounds, and this repression is relieved by the addition of tyramine (1,2). Recently, by using tyramine oxidase-deficient (tynA) and tyramine oxidase-constitutive (tynP tynR) mutants, we demonstrated that the expression of tyramine oxidase induced by tyramine results in derepression of the atsA gene specifying arylsulfatase, which is closely linked to tynA (9,14,16). Tyramine and catechol amines are oxidized by tyramine oxidase to hydroxyphenylacetoaldehyde compounds and ammonium ions, and the enzyme synthesis is subject to catabolite and ammonium repressions (9,15,18).…”

Stimulation of bacterial arylsulfatase activity by arylamines: evidence for substrate activation

“…It is interesting that the tryptamine salts ofp-NPS and p-NCS were also about 25% more susceptible to acid-catalyzed hydrolysis than their K+ counterparts (data not shown). DISCUSSION Although tyramine can increase the bacterial synthesis of arylsulfatase (1,27,28,32,33), the sitmulatory effect of this amine on in vitro arylsulfatase activity in A. oryzae (4) and Pseudomonas sp. strain C12B might be considered unique, since others have noted substantial inhibition of the enzyme with this and related arylamines (32, 34; F. H. Milazzo, personal communication).…”