In 0.05 M potassium phosphate buffer (pH 7.0, ZO”), native rabbit muscle aldolase has been found to exhibit a molecular weight (mn N g, pZ) close to 160,000, in agreement with previous findings. Upon exposure to cold alkaline borate buffer (pH 12.5, p = 0.17, 0”), the enzyme spontaneously dissociates into its monomers which subsequently undergo slow hydrolytic degradation. Compensating for elec...

In 0.05 M potassium phosphate buffer (pH 7.0, ZO”), native rabbit muscle aldolase has been found to exhibit a molecular weight (mn N g, pZ) close to 160,000, in agreement with previous findings. Upon exposure to cold alkaline borate buffer (pH 12.5, p = 0.17, 0”), the enzyme spontaneously dissociates into its monomers which subsequently undergo slow hydrolytic degradation. Compensating for elec...

The activated form of aflatoxin B1 (AFB1) causes covalent modification primarily of guanine residues, leading to alkali-labile sites in DNA. A simple extension of the Maxam-Gilbert procedure for sequence analysis permits the identification of alkali-labile sites induced by AFB1 and determination of the frequency of alkali-labile AFB1 modifications at particular sites on a DNA fragment of known ...

We have examined the induction of alkali-labile regions in DNA of human neoplastic cells treated with 5-fluorouracil and 5-fluorodeoxyuridine. 5-Fluorouracil induces DNA lesions by two mechanisms: incorporation of drug into DNA and a second mechanism not involving the incorporation. The second mechanism is seen in cells treated with aphidicolin, a specific inhibitor of DNA polymerase alpha, to ...

1. Particulate enzyme preparations obtained from Bacillus stearothermophilus B65 by digestion with lysozyme were shown to catalyse teichoic acid synthesis. With CDP-glycerol as sole substrate the preparations synthesized 1,3-poly(glycerol phosphate). It was characterized by alkaline hydrolysis, by glucosylation to the alkali-stable 2-glucosyl-1,3-poly(glycerol phosphate) with excess of UDP-gluc...

DNA damage and repair were studied in a DNA fragment containing the insulin gene after treatment of cells with methylnitrosourea. For these studies, two clonal isolates from the same rat insulinoma cell line which differ in that the insulin gene is transcribed in one (RINr 38) and is silent in the other (RINr B2) were utilized. Both the determination of immunologically reactive insulin released...

Gene damage in cultured human alveolar (L-132) cells induced by exposure to dimethylarsinic acid (DMAA), a major metabolite of inorganic arsenics in mammals, was studied. DNA single-strand breaks and DNA-protein cross-links were induced by the treatment of L-132 cells with 10 mM DMAA. These kinds of damage appeared at 8 hr after start of exposure to DMAA. As regards DNA-protein cross-links, the...

32P-End-labeled restriction fragments derived from pBR322 and pUC9 DNAs were reacted with D-glucosamine or D-glucosamine-6-phosphate in the presence of Cu2+, and, after being heated at 90 degrees C in aqueous piperidine, the DNA products were analyzed on polyacrylamide gels for the sequence-specificity of alkali-labile cleavaged sites. The intensity of oligonucleotide bands of cleavaged sites w...

The site of in vitro ADP-ribosylation of histone H2B was determined. From chromatin of rat liver incubated with [ribose(NMN)-14C]NAD (210 pCi), the histone H2B fraction was extracted with acid and purified by column chromatographies on Bio-Gel P-60 and Sephadex G-150. The final preparation (96 mg of protein), which consisted of ADP-[*4C]ribosylated (1.8 pCi) and nonADP-ribosylated histone H2B’s...

Dermal fibroblast strains from ataxia-telangiectasia (A-T) patients and clinically normal subjects were exposed to 4-nitroquinoline 1-oxide (4NQO) or its 3-methyl derivative (3me4NQO), and their colony-forming abilities and DNA metabolic properties were compared. Three A-T strains, i.e., AT2BE and AT3BI representing genetic complementation group AB and AT4BI belonging to group C, displayed enha...