Disease relevance of hutU

• Cloning and sequencing the urocanase gene (hutU) from Pseudomonas putida [1].
• Digestion of this insert DNA with EcoRI provided a 6.1-kilobase-pair fragment which, upon ligation in pUC8 and transformation into an E. coli host, was found to encode histidine ammonia-lyase and urocanase [2].

High impact information on hutU

• In this study, we describe the activation of urocanase by energy transfer from triplet indole-3-aldehyde, generated in the peroxidase-catalyzed aerobic oxidation of indole-3-acetic acid [3].
• A significant portion of the radioactive material derived from beef liver urocanase also co-crystallized with nicotinic acid [4].
• Both the reversible reducibility of urocanase and its action spectrum of photoreactivation suggest that urocanase contains an enzyme-bound nicotinamide nucleotide molecule which is essential for enzymic activity [4].
• Sodium borohydride-treated inactive urocanase was partially reactivated by light [4].
• Treatment of urocanase with sodium borodeuteride followed by hydrolysis afforded a sample of nicotinic acid which carried deuterium mainly in position 6 [4].

Chemical compound and disease context of hutU

• The histidine-utilizing hutU gene was isolated from a lambda-EMBL3 phage of a genomic library from Pseudomonas putida nicII and subcloned into the expression vector pT7-7 [5].
• Photoactivation of urocanase in Pseudomonas putida. Role of sulfite in enzyme modification [6].
• Although urocanase from Ps. testosteroni is strongly inhibited by NaBH4, no evidence could be obtained for the presence of covalently bound 2-oxobutyrate as a prosthetic group; this is in contrast with findings elsewhere for urocanase from Pseudomonas putida [7].
• Incubation of urocanase from Pseudomonas putida with either its substrate, urocanic acid, or product, 4'(5')-imidazolone-5'(4')-propionic acid, resulted in an oxygen-dependent inhibition of enzyme activity [8].
• Roles of cysteine sulfinate and transaminase on in vitro dark reversion of urocanase in Pseudomonas putida [9].

Biological context of hutU

• The histidine utilization genes hutH and hutU of Pseudomonas putida ATCC 12633 have been mapped by interrupted mating and transduction to a location at approximately 43 minutes on the chromosome, closely linked to ser-800 and met-400 markers previously shown to be at 46 and 42 minutes, respectively [10].
• The inactivation of urocanase was irreversible, could be partially blocked by the competitive inhibitor imidazolepropionate, and involved the modification of a single active-site thiol [8].

Associations of hutU with chemical compounds

• When cloned individually with hutC on the same vector, hutF and hutU (which encodes urocanase) expression was induced by urocanate, indicating that these two genes each possess an operator-promoter element [11].
• Urocanase from Ps. testosteroni does not contain pyridoxal 5'-phosphate as a coenzyme and in this respect is similar to all urocanases studied in purified form [7].
• The inhibition resulted from oxidative decomposition of 4'(5')-imidazolone-5'(4')-propionate but was not due to the formation of the major degradative product, 4-ketoglutaramate, since this compound was not an irreversible inactivator of urocanase although it did produce some inhibition at high concentrations [8].
• We conclude that in P. putida cysteine sulfinate or hypotaurine is catabolized in vivo by a transaminase reaction to sulfite, which modifies urocanase to a form that can be photoactivated [9].
• Porcine crystalline transaminase caused reversion of highly purified P. putida urocanase with cysteine sulfinate and alpha-ketoglutarate [9].

Analytical, diagnostic and therapeutic context of hutU

• 5. Form A of urocanase showed, after treatment with NaBH4 up to 50% inhibition, an elution pattern (TSK-DEAE column) similar to a mixture of forms A, B and C in the approximate ratio of 1:2:1 [12].
• 1. Urocanase, purified by classical methods [Keul, V., Kaeppeli, F., Ghosh, C., Krebs, T., Robinson, J. A. and Rétey, J. (1979) J. Biol. Chem. 254, 843-851] from Pseudomonas putida was submitted to high-performance liquid chromatography on a TSK-DEAE column [12].

References