Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: HUMANGGP:040116 (histone)
 44,835 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The conformational properties of two non-histone chromosomal proteins (high-mobility-group proteins 1 and 2) have been studied by spectroscopic methods. The interaction of high-mobility-group protein 1 with DNA has also been studied. 1. Circular dichroism results indicate that in the presence of salt both proteins are 40-50% helical between pH 1 and 9. Above pH 9 denaturation takes place. In the absence of salt the proteins denature below pH 4. 2. Nuclear magnetic resonance spectra show the presence of ring-current shifted peaks and perturbed aromatic resonances, demonstrating that the helix formation is accompanied by specific tertiary folding. 3. Nuclear magnetic resonance spectra of compelxes between high mobility group protein 1 and DNA demonstrate that a low ionic strength a portion of the molecule rich in lysine and containing all the aromatic residues is bound to DNA, whilst a more acidic region of the chain remains free from the DNA.
 ...
PMID:Conformational studies of two non-histone chromosomal proteins and their interactions with DNA. 0 4

The tyrosine-3-monooxygenase activity [L-tyrosine, tetrahydropteridine: oxygen oxidoreductase (3-hydroxylating); EC 1.14.16.2] of rat adrenal medulla is induced 20-24 hr after the injection of reserpine (16 mumol/kg intraperitoneally). This and other inducing stimuli increase the 3': 5'-cyclic AMP (cAMP) content in the medulla for longer than 60 min and activate the cAMP-dependent protein kinase (ATP: protein phosphotransferase; EC 2.7.1.37) for several hours. Corticotropin (ACTH), dopamine, and propranolol do not induce the monooxygenase, but elicit an increase in the cAMP content of the medulla which fails to activate protein kinase and lasts less than 1 hr. A high- and low-molecular-weight protein kinase are separated by gel filtration from the 20,000 X g pellet extract of adrenal medulla homogenate. The activity of the low-molecular-weight enzyme is expressed as its ability to phosphorylate histone. The protein kinase activity of the pellet is increased between 3 and 17 hr after reserpine injection. Our evidence indicates that this increase is due to a translocation from cytosol to subcellular structures of a kinase that utilizes lysine-rich histone as phosphate acceptor. The protein kinase activity that is extracted from a purified nuclear fraction prepared from the adrenal medulla of rats injected 7 hr previously with reserpine is greater than that extracted from medulla of saline-treated rats.
 ...
PMID:Activation and nuclear translocation of protein kinase during transsynaptic induction of tyrosine 3-monooxygenase. 0 93

The reactivity of the amino groups of histones in chromatin towards acetic anhydride was determined as a function of pH. In the pH range 7-10 the vast majority of amino groups in all five histones are buried. However, at higher pH values some of the histone amino groups become exposed, and the higher the lysine:arginine ratio for the histone the greater was the degree of unmasking observed. At pH 11.8 histone I appears to be completely dissociated, histones IIB1 and IIb2 have approx. 55% of the amino groups unmasked, and histones III and IV have approx. 25% of the amino groups unmasked.
 ...
PMID:Unmasking of histone amino groups in chromatin at high pH. 1 75

Systematic analysis of the hydrolysis of benzyloxycarbonyl (Cbz)-dipeptides by cathepsin A [EC 3.4.12.1] purified from rat liver lysosomes showed that multiple forms of cathepsin A preferentially cleave peptide bonds with leucine, methionine, and phenylalanine. Cbz-Met-Met, -Met-Phe, -Phe-Met, and -Phe-Ala were hydrolyzed 6 to 8 times faster than the standard substrates, Cbz-Glu-Phe and Cbz-Glu-Tyr. The pH optima of the hydrolyses were 4.6 to 5.8. Hydrolysis of peptide bonds with glycine, isoleucine, and proline was very slow, but the rate depended on the nature of the adjacent amino acids. Proteins such as albumin, cytochrome c, gamma-globulin, hemoglobin, histone, myoglobin, and myosin were scarecely degraded. Peptide hormones, such as glucagon and adrenocorticotropic hormone (ACTH) were hydrolyzed markedly with optimum pH's of 4.5 and 4.6, respectively. Angiotensin I, II, bradykinin, Lys- and Met-Lysbradykinin (kallidin and Met-kallidin), and substance P were also hydrolyzed at appreciable rates. pH optima for these peptide hormones were 5.2 to 5.6. On the other hand, insulin and its A chain, luteinizing hormone-releasing hormone (LH-RH), oxytocin and vasopressin were cleaved slowly. In the hydrolyses of glucagon and other peptides, multiple forms of rat liver lysosomal cathepsin A again showed a carboxypeptidase nature, cleaving peptide bonds sequentially from the carboxyl terminal. Almost all of the amino acids were cleaved on prolonged incubation. Vaso-activites of angiotensin II and bradykinin were rapidly lost on hydrolysis by cathepsin A. Lysosomal cathepsin C [dipeptidylaminopeptidase I, EC 3.4.14.1] also activated angiotensin II, but did not inactive bradykinin. Cathepsin A, therefore, can be regarded as one of the lysosomal angiotensinases and kinases. No distinct differences were observed between the multiple forms of cathepsin A in these hydrolyses and inactivations of peptides.
 ...
PMID:Studies on cathepsins of rat liver lysosomes. III. Hydrolysis of peptides, and inactivation of angiotensin and bradykinin by cathepsin A. 1 61

Histones from tissues of young and old rats have been compared. Lysine-rich F1 histone was found to be the only one which is tissue specific and whose subfraction pattern changes in old cells. The comparison of turnover rates of different histones from liver and spleen, measured by the level of 3H-leucine incorporation and subsequent decay of its specific activity with time, showed that while the activity and turnover or arginine-rich histones F3 and F2a2 was reduced in old liver, ageing was associated with increased turnover of F1 histone. The results are discussed from the point of view of a special role of F1 histone in the condensation of chromatin and in the age-related inhibition of some cellular functions.
 ...
PMID:Age changes of turnover rates and subfraction composition of rat liver and spleen histones. 1 50

Methylation of acid proteins and various histone fractions of liver cell chromatin was studied. The intensity of methylation of acid proteins of animals, differing in age, was shown to be 8--16 times higher than that for histone methylation, despite the fact that the rates of 2-14C-methionine incorporation into these two groups of proteins were practically the same. The intensity of methylation of acid proteins and total histones significantly increased during the post-natal development of the animals. Histone methylation largely occurred at the expense of the arginine-rich H3 fraction and the H2 fraction with a moderate level of arginine and lysine. Lysine-rich histone fractions were not subjected to methylation. It is assumed that chromatin proteins methylation regulates conformational properties of the complex and matrix properties of the genome.
 ...
PMID:[Methylation of liver cell chromatin proteins at different stages of post-natal development of albino rats]. 1 28

DNP obtained in low ionic strength solutions (0.7 mM Na-phosphate buffer, pH 7.0) was found to be dissociated under the effect of heparin. The dissociation order of the three histone fractions was established: H2a, H1, H4. The following order of histones is assumed: H2a, H2b, H1, H3, H4. Activation of the DNA and RNA synthesis in the eucaryotic cells, their nuclei and chromatin under the effect of low heparin doses should be associated not with the H1 histone dissociation, but with the dissociation of histones moderately rich in lysine--H2a, and, probably, H2b.
 ...
PMID:[Effect of heparin polyanion on chromatin preparations obtained in solutions of low ionic strength]. 2 36

Antibodies directed against whole histone and purified lysine-rich histone H1 extracted from isolated macronuclei of the ciliate Tetrahymena were obtained and conjugated to fluorescein isothiocyanate. The fluorescein-antibody conjugates were used to directly label Tetrahymena cells. Both macro- and micronuclei were visibly fluorescent in cells stained with anti-whole histone conjugate. However, the anti-H1 conjugate only labeled macronuclei. This in situ demonstration of the lack of positive immunofluorescent staining of micronuclei with anti-H1 conjugate provide further evidence for the absence of H1 in the genetically inactive, mitotically dividing Tetrahymena micronucleus.
 ...
PMID:Immunofluorescence evidence for the absence of histone H1 in a mitotically dividing, genetically inactive nucleus. 6 69

When mouse kidney tissue sections were extracted with 0.1 N hydrochloric acid, sera with antibodies to certain nuclear antigens no longer stained tissue nuclei by immunofluorescence. This effect was due to removal of histones and nuclear acidic proteins Sm and nuclear ribonucleoprotein by the acid. DNA remained in the nuclei of the acid-extracted tissue sections. When solutions of calf thymus histones were reacted with acid-extracted tissues, histones combined with nuclear DNA to form complexes of DNA-histone. These complexes contained antigenic determinants which reacted with sera containing antibodies to deoxyribonucleoprotein to give nuclear staining demonstrated by immunofluorescence. The reaction was immunologically specific in that sera with antibodies to Sm and nuclear ribonucleoprotein were not reactive with reconstituted DNA-histone in nuclei. Other basic proteins such as protamine, poly-L-lysine, and poly-L-arginine could not substitute for histones. The method is introduced as a specific and reproducible assay for study of antibodies to histones.
 ...
PMID:Studies on antibodies to histones by immunofluorescence. 6 91

Staining of nervous tissue sections with ammoniacal silver according to Black et al. has been confirmed to be a reliable histochemical colour reaction for quantitative evaluation of arginine-rich and lysine-rich histones in cell structures on the basis of determinations of the position of spectral curve maximum. Neurons of several brain nuclei which differed in predominating neurotransmitter did not differ in the ratio of arginine-rich to lysine-rich histones while some differences in this ratio were found out in the glial satelite cells adjacent to the corresponding neurons of these nuclei. Moderate circadian fluctuations were observed in the arginine-rich to lysine-rich histone ratio, these fluctuations being rather similar in the neurons studied and in the cells of perineuronal neuroglia.
 ...
PMID:Quantitative microspectral evaluation of the ratio of arginine-rich to lysine-rich histones in neurons and neuroglial cells. 8 97


1 2 3 4 5 6 7 8 9 10 Next >>