Disease relevance of bilirubin

• Formation of a long-lived P+BA- state in plant pheophytin-exchanged reaction centers of Rhodobacter sphaeroides R26 at low temperature [1].
• Upon illumination, the Synechocystis D1/D2/Cyt b559 complex accumulates reduced pheophytin [2].
• This is very similar to the orientation of the pheophytin in purple bacteria reaction centers [3].
• Using an isotope dilution strategy, we have shown that nitrogen fixation can contribute substantial 14N to pheophytin isolated from Medicago truncatula plants grown in symbiosis with Sinorhizobium meliloti [4].
• The predictive values of elevated (PVpos) and normal (PVneg) STBA for disclosing or excluding liver disease, respectively, were not better than the figures for BIL, AP, and ASAT [5].

High impact information on bilirubin

• Kinetics and mechanism of electron transfer in intact photosystem II and in the isolated reaction center: Pheophytin is the primary electron acceptor [6].
• If the reaction centers are prepared in the dark redox state P-700 A X FdB-FdA-, then upon illumination at 11K we observe a different triplet species of uncertain origin, possibly pheophytin or carotenoid [7].
• Primary charge separation in bacterial photosynthesis: oxidized chlorophylls and reduced pheophytin [8].
• This indicates that Cu(II) does not affect the electron transport between P680 and pheophytin [9].
• Photosynthetic reaction center protein D1 contains five membrane-spanning alpha-helices which form binding sites for pheophytin, chlorophyll, carotenoids, quinone, Fe2+, and probably Mn2+ [10].

Chemical compound and disease context of bilirubin

• To assess the diagnostic value of fasting serum total bile acids (STBA) in liver disease, STBA together with serum bilirubin (BIL), serum alkaline phosphatase (AP), and serum aspartate aminotransferase (ASAT) were measured in 66 consecutive patients who had a liver biopsy [5].
• The experiments were performed in intact cells of the cyanobacterium Synechocystis 6803 in which the redox properties of the primary pheophytin electron acceptor, Phe, the primary electron donor, P(680), and the first quinone electron acceptor, Q(A), were modified [11].
• In contrast, synchrony of total algal abundance was low (beta-carotene, pheophytin a, S < 0.10), reflecting low interannual coherence of summer taxa including colonial cyanobacteria and chlorophytes [12].

Biological context of bilirubin

• Experimental evidence suggests that induction of the HO system is an important endogenous mechanism for cytoprotection and that the downstream products of heme degradation, CO, BR, and BV, may mediate these powerful beneficial effects [13].
• 99mTc-DISIDA Vo was inhibited by BR, BSP, ICG and RB, as well as by a rabbit antibody to the rat liver plasma membrane BSP/BR binding protein [14].
• The 15N content of pheophytin, the magnesium-free derivative of chlorophyll, can be measured with great accuracy and precision using positive-ion atmospheric pressure ionization electrospray mass spectroscopy following a simple solvent extraction of small amounts of plant tissue [4].
• Pheophytin a also enhanced signal transduction in the mitogen-activated protein kinase signaling pathway, which is also induced by nerve growth factor [15].
• Recently, a chlorophyll-related compound, pheophytin a, has been identified from an edible green alga, Enteromorpha prolifera (Sujiao-nori in Japanese) as a potent suppressive substance against genotoxin-induced umu C gene expression in a tester bacteria (Okai and Higashi-Okai, 1997, J. Sci. Food Agricul. 71, 531-535) [16].

Anatomical context of bilirubin

• The average pigment stoichiometries (chlorophyll:plastoquinone-9 per 2 pheophytin a) determined using the two data analysis methods were as follows: photosystem II membranes, 274:3.2; photosystem II reaction center complexes, 78:2.5; Synechocystis PS II particles, 55:2.4; photosystem II complexes, 121:2.0 [17].
• Bilirubin (BR) and organic anionic dyes such as sulfobromophthalein (BSP), indocyanine green (ICG) and rose bengal (RB) enter the hepatocyte by a specific non-sodium-dependent membrane transport system [14].
• However, when PC12 cells were treated with a low concentration of pheophytin a (3.9mug/ml) in the presence of a low level of nerve growth factor (10ng/ml), the compound produced neurite outgrowth similar to that produced by a high level of nerve growth factor (50ng/ml) [15].
• Pheophytin a did not itself promote neurite outgrowth of PC12 cells [15].
• (3) Pheophytin a and b from green tea showed inhibitory effects against early induction of ornithine decarboxylase (ODC) in BALB/c mouse skin fibroblasts caused by TPA [18].

Associations of bilirubin with other chemical compounds

• RESULTS: Associations were found between UGT enzyme activities of bilirubin (B) and 4-nitrophenol (NP; r=0.47, P=0.0024), B and 4-methylumbelliferone (MUB; r=0.54, P=0.0003), and NP and MUB (r=0.89, P<0.0001) [19].
• In fact, recent work has demonstrated that administration of exogenous CO, BR, or BV may offer a simple, inexpensive method to substitute for the cytoprotective effects of HO-1 in a variety of clinically applicable models [13].
• The dynamics of the elementary electron transfer step between pheophytin and primary ubiquinone in bacterial photosynthetic reaction centers is investigated by using a discrete state approach, including only the intramolecular normal modes of vibration of the two redox partners [20].
• HPLC monitoring showed that pheophytin agradual degradation (> 90%) was accompanied by a considerable alpha-tocopherol loss (22-35%) due to the reaction of the latter with singlet oxygen [21].
• Our results demonstrate that BR action induces a decrease in DPH and TMA-DPH polarization, FR increases DPH and TMA-DPH polarization, and CR causes only an increase in TMA-DPH polarization in lysosomal membranes [22].

Gene context of bilirubin

• However, these associations were not found in GGT, ALP, or BIL [23].
• The effect of pheophytin a on neurite outgrowth of PC12 cells was completely blocked by U0126, a representative mitogen-activated protein kinase kinase inhibitor [15].
• We show that the method is very sensitive for the detection of contaminants such as the core antenna protein CP47, pigment-free and denatured reaction center proteins, and unbound chlorophyll and pheophytin molecules [24].
• Pigment stoichiometries were determined using two different methods of data analysis and were based on the assumption that there are two pheophytin a molecules per photosystem II reaction center [17].
• The Delta mu values for the Q(x) and Q(y) transitions of H(B) are small (Delta mu = 0.6-1.0 D f(-1)), whereas that of the Q(x) transition of the active pheophytin H(A) is remarkably large (Delta mu = 3 D f(-1)) [25].

Analytical, diagnostic and therapeutic context of bilirubin

• Pigment analysis using reverse-phase HPLC confirmed that contamination by chlorophyll bound to the CP47 apoprotein in the nonresolved RC preparation was low and that the ratio of chlorophyll a to pheophytin a remained 6 when the preparation was separated into its monomeric and dimeric components [26].
• Pheophytin-protein interactions in photosystem II studied by resonance Raman spectroscopy of modified reaction centers [27].
• The efficacy of this device was compared with that of conventional phototherapy devices by measuring the in vitro photodegradation of BR in human serum albumin [28].
• It is concluded that STBA had no diagnostic advantage as compared with the commonly used liver function tests BIL, AP, and ASAT [5].
• Hemoperfusion through albumin-conjugated agarose gel (AAG) effectively removes bilirubin (BR) and other albumin-bound materials from whole blood or plasma [29].

References