Purification and characterization of the main pepsinogen from the shark, Centroscymnus coelolepis.

The main pepsinogen from the mucosa of the shark, Centroscymnus coelolepis, has been purified and characterized. This zymogen, the most abundant protein in terms of quantity and activity (yield 72%), is a homogeneous monomer of molecular weight 42+/-0.7 kDa, as determined by electrophoresis.

Modulation of platelet-activating-factor production by incorporation of naturally occurring 1-O-alkylglycerols in phospholipids of human leukemic monocyte-like THP-1 cells.

1-O-Alkylglycerols (alkyl-Gro), naturally occurring compounds abundant in shark liver oil, protect patients from radiotherapy side-effects. However, the protection mechanism is not well understood. It might be mediated by alkyl-Gro incorporation into pools of platelet-activating factor (PAF) precursor and subsequent modification of PAF biosynthesis.

Mass spectrometric determination of the cleavage sites in Escherichia coli dihydroorotase induced by a cysteine-specific reagent.

Escherichia coli dihydroorotase contains six cysteines/subunit, which are potential ligands of structural and catalytic zinc metals at protein sites of the enzyme. Specific thiol reagents modify, in nondenaturing conditions only, two of these cysteines; these two residues are thought to be ligands of structural zinc. We report here on the localization of these two cysteines on the polypeptide chain through their cyanylation by 2-nitro-5-thiocyanobenzoic acid (NTCB) and the analysis by mass spectrometry of the protein adducts.

Unsaturated glycerol monoethers as novel skin penetration enhancers.

A mixture of glycerol monoethers was extracted from the liver oil of deep sea shark (Centroporus squamosus). It consisted mainly of monoethers of glycerol and linear monounsaturated octadecanol, and glycerol and linear monounsaturated hexadecanol. Only about 11% of the extract consisted of glycerol monoethers derived from linear saturated fatty alcohols.