Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.1 (chymotrypsin)
 10,938 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In order to study the antigenic structure of histone H1(0) the purified protein from mouse liver was subjected to different chemical and enzymatic treatments (CNBr, acetic acid, trypsin, chymotrypsin). The resulting peptides were fractionated in SDS-containing or acid-urea polyacrylamide gels, transferred by electroblotting onto nitrocellulose paper and probed with specific rabbit anti-H1(0) antiserum. The C-terminal fragments 99-193 (obtained following acetic acid hydrolysis) and 107-193 (obtained by chymotrypsin digestion) also exhibited strong immunoreactivity. Fragment 1-30 (CNBr cleavage) contained antigenic determinants while the shorter fragments 1-22 and 1-28 (acetic acid hydrolysis) failed to show any detectable reactivity. It was concluded that, in contrast to histone H5 whose reactivity is mainly concentrated to the globular domain of the molecule, the antigenic determinants in histone H1(0) are more or less evenly distributed along the polypeptide chain with the possible exception of the short unstructured N-nose.
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PMID:Antigenic structure of histone H1(0). 172 85

Histone H1t has been purified from rat testes and antibodies were elicited in rabbits. Immunoblotting studies with anti-histone H1t-IgG have shown that it reacted specifically with histone H1t but not with other histone H1 subtypes, namely H1a, -b, -c, -d, -e and H10. The anti-histone H1t-IgG also did not react with chicken erythrocyte histone H5. Immunoblotting studies have also revealed that the polyclonal anti-histone H1t-IgG reacted with (a) two polypeptide fragments, NBS-N and NBS-C, derived from N-bromosuccinimide cleavage of histone H1t, (b) two polypeptide fragments, CT-N and CT-C, derived from alpha-chymotrypsin cleavage of histone H1t, and (c) GH1t, globular domain of histone H1t obtained after trypsin cleavage. The indirect immunofluorescence studies on nuclei isolated from adult rat testes with anti-histone H1t-IgG showed that the fluorescence, particularly, of the pachytene nucleus was the brightest. On the other hand, anti-histone H1t-IgG did not stain nuclei from either liver or nuclei isolated from the testes of 10-day-old rats.
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PMID:Testis-specific histone H1t is antigenically distinct among H1 subtypes. 241 27

Four histone H1 subtypes and H1(0) were fractionated from human placental nuclei and purified to homogeneity by a combination of Bio-Rex 70 chromatography and reverse-phase high-performance liquid chromatography (RP-HPLC). Polyclonal antibodies were generated in rabbits against one of these subtypes designated H1-3. Antibodies reacted only against this subtype in enzyme-linked immunosorbent assays and Western assays; subtype specificity was documented further by Western blotting of cell and nuclear extracts. They crossreacted with monkey H1, but not with H1 from other vertebrates tested. The epitope(s) recognized were mapped by immunoblotting against peptides prepared by cleavage with N-bromosuccinimide (NBS) and alpha-chymotrypsin; it includes the variant amino-terminal tail of the protein as well as a portion of the globular domain. The antibody stains mitotic chromosomes weakly but uniformly and, unlike antibodies that recognize total H1 which show uniform nuclear staining after indirect immunofluorescence localization, anti-H1-3 exhibits preferential labelling of the nuclear periphery. This non-uniform staining suggests compartmentalization of this subtype which may have functional significance with respect to differential chromatin condensation.
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PMID:Fractionation of human H1 subtypes and characterization of a subtype-specific antibody exhibiting non-uniform nuclear staining. 751 70

Histone H1(0) is known to consist of two subfractions named H1(0)a and H1(0)b. The present work was performed with the aim of elucidating the nature of these two subfractions. By using reversed-phase high performance liquid chromatography in combination with hydrophilic interaction liquid chromatography, we fractionated human histone H1(0) into even four subfractions. Hydrophilic interaction liquid chromatographic analysis of the peptide fragments obtained after cleavage with cyanogen bromide and digestion with chymotrypsin suggested that the four H1(0) subfractions differ only in their small N-terminal end of the H1(0) molecule (30 residues). Edman degradation of the N-terminal H1(0) peptide fragments and mass spectra analysis have indicated that human histone H1(0) consists of intact histones H1(0) (named H1(0) Asn-3) and deamidated H1(0) forms (H1(0) Asp-3) having an aspartic acid residue at position 3 instead of asparagine. Moreover, both H1(0) Asn-3 and H1(0) Asp-3 are blocked (H1(0)a Asn-3, H1(0)a Asp-3) and unblocked (H1(0)b Asn-3, H1(0)b Asp-3) on their N terminus. Acid-urea gel electrophoretic analysis has shown that the histone subfraction, in the literature originally named H1(0)a, actually consists of a mixture of H1(0)a Asn-3 and H1(0)a Asp-3, whereas H1(0)b consists of H1(0)b Asn-3 and H1(0)b Asp-3. Furthermore, we found that hydrophilic interaction liquid chromatography separates rat and mouse histone H1(0) just like human H1(0) into four subfractions. Hydrophilic interaction liquid chromatographic analysis of brain and liver histone H1(0) from rats of different ages revealed an age-dependent increase of both the N-terminally acetylated and the deamidated forms of H1(0). In addition, we found that the relative proportions of the four forms of H1(0) histones differ from tissue to tissue.
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PMID:The microheterogeneity of the mammalian H1(0) histone. Evidence for an age-dependent deamidation. 958 79