The benzene dioxygenase from Pseudomonas putida ML2 is a multicomponent complex comprising a flavoprotein reductase, a ferredoxin, and a terminal iron-sulfur protein (ISP). The catalytic activity of the isolated complex shows a nonlinear relationship with protein concentration in cell extracts, with the limiting factor for activity in vitro being ferredoxin(BED). The relative levels of the thre...

Cancer patients mount T-lymphocyte responses against antigens expressed selectively by their malignancy, but these responses often fail to control their disease, because tumors select mechanisms that allow them to resist immune destruction. Among the numerous resistance mechanisms that have been proposed, metabolic inhibition of T cells by tryptophan catabolism deserves particular attention, be...

Sphingomonas sp. strain RW1 synthesized a constitutive enzyme system that oxygenated dibenzofuran (DBF) to 2,2',3-trihydroxybiphenyl (THB). We purified this dibenzofuran 4,4a-dioxygenase system (DBFDOS) and found it to consist of four components which catalyzed three activities. Two isofunctional, monomeric flavoproteins (components A1 and A2; M(r) of about 44,000) transferred electrons from NA...

Pseudomonas putida GJ31 has been reported to grow on chlorobenzene using a meta-cleavage pathway with chlorocatechol 2,3-dioxygenase (CbzE) as a key enzyme. The CbzE-encoding gene was found to be localized on the 180 kb plasmid pKW1 in a cbzTEXGS cluster, which is flanked by transposases and encodes only a partial (chloro)catechol meta-cleavage pathway comprising ferredoxin reductase, chlorocat...

Our abilities to detect and enumerate pollutant-biodegrading microorganisms in the environment are rapidly advancing with the development of molecular genetic techniques. Techniques based on multiplex and real-time PCR amplification of aromatic oxygenase genes were developed to detect and quantify aromatic catabolic pathways, respectively. PCR primer sets were identified for the large subunits ...

Cancer patients mount T-lymphocyte responses against antigens expressed selectively by their malignancy, but these responses often fail to control their disease, because tumors select mechanisms that allow them to resist immune destruction. Among the numerous resistance mechanisms that have been proposed, metabolic inhibition of T cells by tryptophan catabolism deserves particular attention, be...

A method was developed for the purification of catechol 1, 2-dioxygenase from Rhodococcus rhodochrous NCIMB 13259 that had been grown in the presence of benzyl alcohol. The enzyme has very similar apparent Km (1-2 microM) and Vmax (13-19 units/mg of protein) values for the intradiol cleavage of catechol, 3-methylcatechol and 4-methylcatechol and it is optimally active at pH9. Cross-linking stud...

This article highlights the evidence linking depression to increased inflammatory drive and explores putative mechanisms for the association by reviewing both preclinical and clinical literature. The enzyme indoleamine 2,3-dioxygenase is induced by proinflammatory cytokines and may form a link between immune functioning and altered neurotransmission, which results in depression. Increased indol...

Sre1, the fission yeast sterol regulatory element binding protein, is an endoplasmic reticulum membrane-bound transcription factor that responds to changes in oxygen-dependent sterol synthesis as an indirect measure of oxygen availability. Under low oxygen, Sre1 is proteolytically cleaved and the released N-terminal transcription factor (Sre1N) activates gene expression essential for hypoxic gr...