Phosphorylation of rabbit skeletal muscle glycogen synthase in vivo in response to hormones was investigated. Methods were developed to purify the synthase without altering its kinetic parameters, thereby indicating constancy of the synthase phosphorylation state. The enzyme from control rabbits had an activity ratio (-glucose-6-P/+glucose-6-P) of 0.24, K, for glucose-6P of 0.17 m ~ , and K , f...

Cultures of fibroblasts from newborn rats and successive subcultures of these cells were treated with 4-nitroquinoline-1-oxide to induce DNA repair. DNA from the cultures was examined by velocity sedimentation in alkaline sucrose gradients immediately after drug treatment and after a post-treatment incubation period of 3 h. Early passage cells were able to repair the damage that appeared as sin...

The (6-4) photoproduct formed by ultraviolet light is known as an alkali-labile DNA lesion. Strand breaks occur at (6-4) photoproducts when UV-irradiated DNA is treated with hot alkali. We have analyzed the degradation reaction of this photoproduct under alkaline conditions using synthetic oligonucleotides. A tetramer, d(GT(6-4)TC), was prepared, and its degradation in 50 mm KOH at 60 degrees C...

The present study was undertaken to investigate changes in the acid-phosphate content of porcine enamel mineral during its development and to assess separately the HPO4(2-) pools in labile and stable forms. Enamel samples at the secretory and maturing stages of amelogenesis were obtained from the permanent incisors of five- to six-month-old slaughtered piglets. Human enamel from erupted, extrac...

Ultraviolet light induces alkaline labile lesions in DNA. These lesions occur at the bipyrimidine sites T-C, C-C, and T-T, and do not result from the formation of pyrimidine cyclobutane dimers. To examine the chemical nature of the alkaline labile lesions, pyrimidine dinucleotides (2'-deoxythymidylyl-(3' leads to 5')-2'-deoxycytidine, 2'-deoxythymidylyl-(3' leads to 5')-2'-deoxythymidine, 2'-de...

Regenerating blood of geese suffering from phenylhydrazine anaemia was separated into ' mature' and ' immature' cell populations by centrifugation through a barrier of BSA. Socalled 'mature cells' consisted of mainly mature erythrocytes and 'immature cells' included twothirds polychromatic and younger erythroblasts. Histone proteins, dissociated from isolated nuclei of both populations of cells...

To cope with a sudden increase in the external pH value to 8.9, Bacillus subtilis cells induce about 80 genes which can be divided into two classes. Most of these genes are members of the sigma(W) regulon, while some are under the control of so-far-unknown transcriptional regulators. The genes of the pst operon belong to the second class. Here, we attempted to answer the questions of why and ho...

1. Ox-brain microsomes were incubated with [gamma-(32)P]ATP under various conditions. After the reaction, which was stopped with trichloroacetic acid, a small amount of phosphate remained bound to the washed precipitate. 2. Properties of the bound phosphate were studied by treatment with buffers and solvents. 3. The Na(+)-dependent increment in bound phosphate, predominant at low ATP concentrat...

The photoreactions of 9-[6-(4-azidobenzamido)hexylamino]acridine (AHA) and 9-[6-(2-diazocyclopentadienylcarbonyloxy)hexylamino]acridine (DHA) with double stranded DNA result in formation of single strand nicks and alkali labile sites (adducts) with an efficiency of 6 x 10(-3) nicks per AHA and 3 x 10(-2) nicks per DHA molecule. The alkali dependent DNA cleavage by AHA shows a pronounced A+G pre...