Shielding of protein-boronate interactions during boronate chromatography of neoglycoproteins.

A method for separating glycoproteins on a boronate column under conditions which suppress the interactions between the protein moiety and the boronic acid ligand has been developed. A model system consisting of non-glycosylated chymotrypsin and maltose-modified chymotrypsin (cht-mal) was utilised in the investigations. Chymotrypsin was chosen as the model protein because of its known interaction with boronate. By coupling maltose to chymotrypsin, a neoglycoprotein was created which has the property of binding to the affinity matrix both via the protein moiety and via the carbohydrate residues. The introduction of a so-called shielding reagent into the buffer solutions during chromatography resulted in the prevention of the protein-boronate interactions while the carbohydrate-boronate interaction was little influenced. Different types of, mainly low-molecular-mass, polyhydroxyl chemicals were screened in order to correlate the shielding efficiency to the chemical structure of the investigated compounds. Polyhydroxyl chemicals with a conformation that allows the formation of tridentate complexes with the boronate anion provided the highest shielding efficiencies.

Autosomal dominant myofibrillar myopathy with arrhythmogenic right ventricular cardiomyopathy linked to chromosome 10q.

Twenty-one members of a Swedish family suffering from myopathy and cardiomyopathy underwent neurological and cardiological investigations. Medical charts of 2 affected deceased patients were reviewed. Twelve patients had myopathy. The distribution of weakness was axial in mildly affected, axial and predominantly distal in moderately affected, and generalized in severely affected patients. The electromyogram showed signs of myopathy in 10 patients. Muscle biopsy specimens showed myopathic changes, rimmed vacuoles, and accumulation of desmin, dystrophin, and other proteins. Electron microscopy revealed granulofilamentous changes and disorganization of myofibrils. Several patients had episodes of chest pain or palpitations. Three men had arrhythmogenic right ventribular cardiomyopathy. Nonsustained ventribular tachycardia, atrial flutter, and dilatation of the ventricles mainly affecting the right ventricle were documented. Two of them had a pacemaker implanted because of atrioventricular block and sick sinus syndrome. Inheritance is autosomal dominant with variable onset and severity of skeletal muscle and cardiac involvement. Linkage analysis of candidate chromosomal regions showed a maximum 2-point LOD score of 2.76 for marker locus D10S1752 on chromosome 10q. A multipoint peak LOD score of 3.06 between markers D10S605 and D10S215 suggests linkage to chromosome 10q22.3, and this region may harbor a genetic defect for myofibrillar myopathy with arrhythmogenic right ventricular cardiomyopahty.