Decreased viscosity of rat-liver DNA treated by 3'-methyl-4-dimethylaminoazobenzene, detected with a new viscometric approach

DNA damage induced in vivo by 3'-methyl-4-dimethylaminoazobenzene (3'CH3DAB) was investigated with 2 differently sensitive techniques: the alkaline elution assay and the viscometric measurement of DNA damage. 3'CH3DAB appeared to be falsely negative with the alkaline elution assay, whereas with the viscometric approach, which is about 30-50 times more sensitive, it appeared positive, and the DNA damage was dose-dependent.     

Rapid purification and properties of human glycodelin (endometrial α2-globulin)

The method presented can easily produce milligram amounts of glycodelin from pregnancy endometrium, with a 19% yield. It involves anion-exchange chromatography, gel permeation and chromatofocusing; it results in one stainable band at M_r 28 000 after sodium dodecyl sulphate–polyacrylamide electrophoresis, as well as after immunoblot analysis, performed using an affinity-purified IgG fraction from an antiserum against glycodelin. In spite of this, the corresponding gel isoelectric focusing pattern gives four stainable bands with pI values between 4.55 and 5.2. Western immunoblot analysis of tissue extracts indicates the presence of glycodelin epitopes associated with materials heavier than the native protein. Circular dichroism spectra of the highly purified protein in water solutions indicate a large amount of β-sheet conformation, whereas those obtained with different proportions of 2-propanol in water, show an increased proportion of α-helix conformation.     

Immunological properties of a radioiodinated monoclonal antibody and its F(ab')2mu fragments directed against the polymorphic epithelial mucin of human breast cancer.

The purification of the IgM monoclonal antibody 436 against a breast tumor antigen from mouse ascitic fluid is reported. The purified immunoglobulin was radioiodinated and the resulting product assessed for its binding capacity and binding specificity. Purified IgM-436 served for F(ab')2 mu preparation which was tested for its antigen binding capacity. Radioiodinated IgM-436 and its F(ab')2 mu retained their immunological activity which was never lower than those of the corresponding cold products.     

Substituted 6-aminonaphthalene-1-sulfamides as fluorogenic indicators groups for synthetic proteinase substrates]

Alkyl substituted 6-aminonaphthalene-1-sulphamides (ANSA), hydrobromides of substituted 6-(N alpha-benzyloxycarbonyl-L-arginyl)aminonaphthalene-1-sulphamides (Z-Arg-ANSA) and hydrobromides of 6-(benzyloxycarbonylglycylglycyl-L- arginyl)aminonaphthalene-1-sulphamides (Z-Gly-Gly-Arg-ANSA) are synthesized and their absorption and emission spectra measured. ANSA have an emission band at 470-480 nm, comparable or exceeding in intensity that of compounds used as fluorogenic leaving groups in peptide cleavage reactions. The bands of Z-Arg-ANSA and Z-Gly-Gly-Arg-ANSA are shifted to the short-wave side and do not overlap with ANSA's emission band. Reactions of Z-Arg-ANSA and Z-Gly-Gly-Arg-ANSA with trypsin were studied. The kinetic parameters (kcat and Km) of the reaction of Z-Arg-ANSA were found to depend on the nature and the number of substituents in the sulphamide. In the case of Z-Gly-Gly-Arg-ANSA, this dependence is negligible and kcat/Km exceeds by over ten times this parameter of Z-Arg-ANSA. ANSA can apparently be used in the synthesis of fluorogenic substrates of proteases.