Aberrant methylation patterns of genomic DNA are well-studied epigenetic mutations in cancer. Hypermethylation of CpG islands in tumor-suppressor genes promotes oncogenesis and hypomethylation of global genomic DNA affects genomic stability. Cancer is recognized as a genetic and epigenetic disease. However, it is not clear how epigenetic regulatory factors, including histone modification enzyme...

Chemical modification of aminopeptidase from pronase has revealed two important histidines in enzyme catalysis. In the absence of metal ions, modification of the readily-modified histidine (pKa 6.9 +/- 0.5) results in a drastic loss of activity, indicating that this residue is indispensible for enzyme activity. In the presence of CaCl2, the modified enzyme still retains approx. 60% of the activ...

Video techniques were used to record changes in motility of cells of Streptococcus sp. strain V4051 exposed to a variety of protein modification reagents. Starved cells were tethered to glass by a single flagellum, energized metabolically with glucose, or treated with valinomycin and energized artificially via shifts to media containing low concentrations of potassium ion. Experiments were devi...

Sodium carboxymethyl starch (CMS) was prepared using an extruder as a continuous solvent-less chemical reactor. The effects of NaOH, H2O, temperature, ethanol, sodium mono chloro acetate (SMCA), sodium tripolyphosphate (STPP), citric acid, epichlorohydrin and screw configuration on the degree of substitution (DS) and swelling properties of CMS were studied. Using these factors, CMS with the DS ...

This paper presents an experimental study on the static and dynamic mechanical properties of nonwoven based flax fibre reinforced polypropylene composites. The effect of zein modification on flax fibres is also reported. Flax nonwovens were treated with zein coupling agent, which is a protein extracted from corn. Composites were prepared using nonwovens treated with zein solution. The tensile, ...

Chemical reactivity of cytosines in 32P-labeled E. coli tRNA1Leu, E. coli tRNAPhe and yeast tRNAPhe before and after aminoacylation was examined by use of a cytosine-specific reagent, semicarbazide-bisulfite mixture. In all the three tRNA species examined, the cytosine residues that were susceptible to the modification were the same in the aminoacylated tRNA and the unacylated tRNA. Only a limi...

Many effects of dibenamine (Â /V-dibenzyl-/?chloroethylamine) on physiological systems have been reviewed by Graham1 and Nickerson2. However their effect on enzyme activity was not reported till Beddoe and Smith 3 observed that dibenamine also reacts with acetylcholinesterase under rather specific conditions in an irreversible manner to give an in­ active modified enzyme. The inhibiting compoun...

5. GUTFREUND, El., Trans. Faraday Sot., 61, 441 (1955). 6. WALBFI, K. A., KAUFFMAN, D. L., SAMPATH KUMAR, K. S. V., AND NEURATE, H., Proc. Natl. Ad. Sci. U. S., 51, 301 (1964). 7. WALSH, K. A., AND NEURATH, H., Proc. Nail. Acad. Sci. U. S., 52, 884 (1964). 8. MARE&GUIA, M., AND SHAW, E., Federation Proc., 22, 528 (1963). 9. CRESTFIELD, A. M., STEIN, W. H., AND MOORE, S., J. Bid. Chem., 238, 241...

Sulfhydryl reagents, as well as mild hydrogen peroxide oxidation, do not inhibit the activity of yeast phosphoglycerate kinase, indicating that the single thiol group and 3 methionine residues present in the enzyme are not essential for activity. Nitration of phosphoglycerate kinase by tetranitromethane inhibits the enzyme by reaction with a single tyrosine residue. Substrates provide partial p...