Lucina pectinata

FIGURE 8.5 Multiple-sensor respirometry. Representative calibration traces of PNOS (thin line, left ordinate) and PHSS (thick line, right ordinate) operating simultaneously in PBS, pH 7.3 at 37°C, with 50pM DTPA in a closed chamber respirometer. After NO additions were made, the chamber solution was replaced with fresh buffer, to which Na2S stock solutions were then injected in a stepwise manner. The stable POS signal shown at 2 pM 02 demonstrates that the POS does not respond to NO or H2S. Injections of anoxic buffered NO and H2S stocks are shown with concentrations at arrows, as are additions of Lucina pectinata ferric hemoglobin I (metHb I), which stoichiometrically binds to H2S (after [41]). 

FIGURE 8.8 H2S production in vascular tissues. IPS production by aorta homogenate (upper panel), cultured rat vascular smooth muscle cells (VSMCs middle panel), and intact rat aorta occurs after the addition of substrate L-cysteine (L-cys) and cofactor pyridoxal L-phosphate (PLP) for the enzyme CGL located in vascular tissue. H2S production is inhibited after the CGL. 3 cyano-L-alanine (BCA) is added. Ferric Lucina pectinata hemoglobin I (metHb) is added to confirm H2S production. The quantity of metHb-sulfide produced, determined spectrophotometrically, matched the levels of H2S detected by the PHSS (after [41]). 

D.W. Kraus and J.B. Wittenberg, Hemoglobins of the Lucina pectinata bacteria symbiosis I. Molecular properties, kinetics, and equilibria of reactions with ligands. J. Biol. Chem. 265, 16043—16053 (1990). 

Ultrafast studies of ferric complexes of Hemoglobin I from Lucina pectinata... 

A cytoplasmic hemoglobin of the clam Lucina pectinata has evolved to carry oxygen to symbiotic chemoautotrophic bacteria located within cells of the host s gills. It is also readily oxidized to the Fe3+ methemoglobin form which binds sulfide ions extremely tightly180 182 and is thought to transport sulfide to the bacteria. 

Ultrafast studies of ferric complexes of Hemoglobin 1 from Lucina pectinata E. Ramirez, C. Ramos, M. Rodriguez, R. Pietri, M. Chergui and... 

---