Validation of a SPE HPLC-UV method for the quantification of a new ER-specific photosensitizer OR-141 in blood serum using total error concept.

The aim of this work is to develop the first validated HPLC-UV method quantification in blood serum for a new endoplasmic reticulum (ER)-specific benzophenazine photosensitizer (OR-141). A fast solid phase extraction (SPE) cleaning sample procedure was achieved on C18 encapped (ec) SPE cartridges and the separation was performed on a RP-18e column (5μM) using an isocratic elution with methanol. The method has been fully validated according to accuracy profiles based on total error and tolerance intervals.

Organized proteomic heterogeneity in colorectal cancer liver metastases and implications for therapies.

Unlabelled: Tumor heterogeneity is a major obstacle for developing effective anticancer treatments. Recent studies have pointed to large stochastic genetic heterogeneity within cancer lesions, where no pattern seems to exist that would enable a more structured targeted therapy approach. Because to date no similar information is available at the protein (phenotype) level, we employed matrix assisted laser desorption ionization (MALDI) image-guided proteomics and explored the heterogeneity of extracellular and membrane subproteome in a unique collection of eight fresh human colorectal carcinoma (CRC) liver metastases.

Structural determinants of specificity and catalytic mechanism in mammalian 25-kDa thiamine triphosphatase.

Background: Thiamine triphosphate (ThTP) is present in most organisms and might be involved in intracellular signaling. In mammalian cells, the cytosolic ThTP level is controlled by a specific thiamine triphosphatase (ThTPase), belonging to the CYTH superfamily of proteins. CYTH proteins are present in all superkingdoms of life and act on various triphosphorylated substrates.

High inorganic triphosphatase activities in bacteria and mammalian cells: identification of the enzymes involved.

Background: We recently characterized a specific inorganic triphosphatase (PPPase) from Nitrosomonas europaea. This enzyme belongs to the CYTH superfamily of proteins. Many bacterial members of this family are annotated as predicted adenylate cyclases, because one of the founding members is CyaB adenylate cyclase from A.

A specific inorganic triphosphatase from Nitrosomonas europaea: structure and catalytic mechanism.

The CYTH superfamily of proteins is named after its two founding members, the CyaB adenylyl cyclase from Aeromonas hydrophila and the human 25-kDa thiamine triphosphatase. Because these proteins often form a closed β-barrel, they are also referred to as triphosphate tunnel metalloenzymes (TTM). Functionally, they are characterized by their ability to bind triphosphorylated substrates and divalent metal ions.

Thiaminylated adenine nucleotides. Chemical synthesis, structural characterization and natural occurrence.

Thiamine and its three phosphorylated derivatives (mono-, di- and triphosphate) occur naturally in most cells. Recently, we reported the presence of a fourth thiamine derivative, adenosine thiamine triphosphate, produced in Escherichia coli in response to carbon starvation. Here, we show that the chemical synthesis of adenosine thiamine triphosphate leads to another new compound, adenosine thiamine diphosphate, as a side product.