Active Carboxylic Acid-Terminated Alkanethiol Self-Assembled Monolayers on Gold Bead Electrodes for Immobilization of Cytochromes c

It is extremely difficult to immobilize cytochrome c (cyt c) on carboxylic acid-terminated alkanethiol self-assembled monolayers (HOOC-SAM) on gold bead electrodes prepared in a hydrogen flame. We found that simple pretreatment of a HOOC-SAM/gold bead electrode by potential cycling in buffer solution in the range ±300 mV prior to immobilization of the protein facilitated stable cyt c binding to HOOC-SAMs. The stability of cyt c on the HOOC-SAMs is independent of the topology of the gold surface

Electron Tunneling through Pseudomonas aeruginosa Azurins on SAM Gold Electrodes

Robust voltammetric responses were obtained for wild-type and Y72F/H83Q/Q107H/Y108F azurins adsorbed on CH_3(CH_2)_nSH:HO(CH_2)_mSH (n=m=4,6,8,11; n=13,15 m=11) self-assembled monolayer (SAM) gold electrodes in acidic solution (pH 4.6) at high ionic strengths. Electron-transfer (ET) rates do not vary substantially with ionic strength, suggesting that the SAM methyl headgroup binds to azurin by hydrophobic interactions. The voltammetric responses for both proteins at higher pH values (>4.6 to 11) also were strong. A binding model in which the SAM hydroxyl headgroup interacts with the Asn47 carboxamide accounts for the relatively strong coupling to the copper center that can be inferred from the ET rates. Of particular interest is the finding that rate constants for electron tunneling through n = 8, 13 SAMs are higher at pH 11 than those at pH 4.6, possibly owing to enhanced coupling of the SAM to Asn 47 caused by deprotonation of nearby surface residues

Extended Hemi-Hepatectomy with Portal Vein Reconstruction in a Patient with Situs Ambiguous

We report a case of far-advanced hepatocellular carcinoma (HCC) with situs ambiguous, complex visceral and vascular anomalies, who was successfully managed by extended hemi-hepatectomy. A 67-year-old man was referred to our hospital with a large liver mass. Abdominal ultrasonography, computed tomography and angiography revealed HCC with a diameter of 10 cm, with tumor thrombus in the main and first branch of the portal vein. Multiple complex anomalies in the abdomen were determined preoperatively. He had right-sided spleens-stomach-duodenum, liver at midline, inferior vena cava interruption with azygous continuation, and hepatic arterial anomaly. Extended left lobectomy of the liver with reconstruction of the portal vein was performed. Postoperatively, the patient recovered without major complications, and he was discharged on postoperative day 21. We report the first successful extended hepatectomy with portal vein reconstruction for HCC in a patient with rare situs anomalies

Full assignment of heme redox potentials of cytochrome c3 of D. vulgaris Miyazaki F by 1H-NMR

AbstractSite-specific heme assignment of the 1H-NMR spectrum of cytochrome c3 of D. vulgaris Miyazaki F, a tetraheme protein, was established. The major reduction of the heme turned out to take place in the order of hemes I, III, IV and II (numbering in the crystal structure). The hemes with the smallest and greatest solvent accessibility were reduced at the highest and lowest potentials on average, respectively. A cooperative interheme interaction was attributed to a pair of the closest hemes, namely, hemes III and IV. This assignment can provide the physicochemical basis for the elucidation of electron transfer of this protein