Coproporphyrins,Uroporphyrins, and Their Metal Comlexes: Biosynthesis and Application to Immune Analysis and Diagnostic Methods

Methods of synthesis of coproporphyrin and uroporphyrin by using bacteria of the genus Arthrobacterare proposed. Metal complexes of coproporphyrin and uroporphyrin with Pt, Pd, and Zn were synthesized. Their structures were identified by spectrophotometry, IR spectrometry, ¹H-NMR, mass spectrometry, and HPLC. Data showing the possibility of using coproporphyrin III–metal complexes as luminophores for fluorescence detection of tumors was gathered. The current and prospective uses of metal complexes of water-soluble natural porphyrins in advanced immunofluorescence assays are discussed.     

Superoxide Dismutase and Catalase Activities in Carotenoid-Synthesizing Fungi Blakeslea trispora and Neurospora crassa Fungi in Oxidative Stress

The addition of menadione into the medium during cultivation ofNeurospora crassa in the dark activated its constitutive superoxide dismutase. Exposure to light not only activated superoxide dismutase and catalase, but also increased the content of neurosporaxanthin. Superoxide dismutase activity in the mixed (+/–) cultures of Blakeslea trispora synthesizing -carotene in the dark was much lower than that inNeurospora crassa. The superoxide dismutase activity and catalase activity further decreased in oxidative stress with a parallel increase in the content of -carotene. Our results indicate that neurosporaxanthin possesses photoprotective properties in Neurospora crassa. In Blakeslea trispora (+/–) fungi, -carotene acts as a major antioxidant during inactivation of enzymes that detoxify reactive oxygen species.     

Salvage pathway for NAD biosynthesis in Brevibacterium ammoniagenes: regulatory properties of triphosphate-dependent nicotinate phosphoribosyltransferase

As the rate-limiting enzyme, catalyzing the first reaction in NAD salvage synthesis, nicotinate phosphoribosyltransferase (NAPRTase, EC 2.4.2.11) is of important interest for studies of intracellular pyridine nucleotide pool regulation. We have purified NAPRTase 520-fold from Brevibacterium ammoniagenes ATCC 6872 without using an over-expression system by applying acid treatment, salt fractionation, Ca-phosphate gel treatment, anion exchange column chromatography and size-exclusion gel filtration. Unlike this enzyme from other sources, B. ammoniagenes NAPRTase was found to be controlled by the feedback inhibition by the end product NAD with K(i)=0.7+/-0.1 mM. The reaction products, pyrophosphate and nicotinate mononucleotide, also decreased the enzyme activity, as did other intermediates of NAD synthesis, such as AMP, ADP and a NAD direct precursor, nicotinate adenine dinucleotide or deamido NAD. The enzyme was observed to require a nucleoside triphosphate for its activity and showed the maximum affinity for ATP. The specificity, however, turned out to be poor, and ATP could be substituted by other nucleoside triphosphates as well as by sodium triphosphate. The kinetic characteristics of the enzyme are reported. For the first time, our data have experimentally revealed such complicated stimulatory and inhibitory effects by the intermediates of NAD biosynthesis on one of its salvage enzymes, NAPRTase. On the basis of these data, the key role of NAPRTase is discussed in light of the regulation of NAD metabolism in B. ammoniagenes.     

Effect of nucleotide containing corrinoids on vitamin B 12 synthesis in Propionibacterium shermanii]

The influence of B12-CN, B12-OH, coenzyme B12, factor III and factor B on the synthesis of vitamin B12 and porphyrins by different strains of P. shermanii was investigated. Neither compound inhibited the development of propionic bacteria or suppressed porphyrin formation. All nucleotide containing analogues of vitamin B12 produced a strong repressive effect on the synthesis of corrinoid compounds regardless of the modifications in the upper and lower cobalt ligands. Factor B containing no nucleotide moiety did not show this effect. It is suggested that the nucleotide moiety of the vitamin B12 molecule is responsible for the binding of vitamin to protein aporepressor.