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Biomedical subjects

G Biserte

Publications and source records attributed to G Biserte.

At least 55 records · Page 3Linked to original sources
PubMed1976

[Guinea pig liver cytosol has an L-threonine deaminase activity distinct from L-serine deaminase].

Using sodium sulfate precipitation, "Sephadex G200" gel filtration and polyacrylamide gel electrophoresis, a L-threonine desaminase was demonstrated in the Guinea-Pig liver cytosol. This enzyme was separated from the guinea pig liver L-serine desaminase possessing an auxiliary activity on L-threonine substrate described by us in a previous work. The optimals for pH (7,1) and temperature (+ 55 degrees C) and the apparent molecular weight (134,000 + 20,000) were established.

Animals↗
PubMed1976

Primary structure and microheterogeneities of rat chloroleukemia histone H2A (histone ALK, IIbl or F2a2).

Rat chloroleukemia histone H2A, obtained from the F2a2 fraction, has been eluted in two peaks from a Biorex 70 column. The amino acid sequence of rat chloroleukemia histone H2A has been determined and compared to that of calf-thymus histone H2A. The structural studies performed on the tryptic peptides from the maleylated histone and on the thermolysin peptides from the native histone clearly demonstrate the existence of three molecular species of histone H2A depending on the nature of the amino acid residue at positions 16 and 99: H2A-alpha (Ser-16 and Lys-99) accounts for 60% and H2A-betaI (Thr-16 and Arg-99) and H2A-betaII (Ser-16 and Arg-99) for 20% each. A threonine residue at position 16 and a lysine residue at position 99 have been found in calf-thymus histone H2A.

Amino Acid Sequence↗
PubMed1976

[Studies on the activities of peptidases from human leucocytes, and human and guinea pig alveolar macrophages (author's transl)].

Peptidases activities were compared in human leucocytes, guinea pig and human alveolar macrophages. Seversl endo- and exopeptides were characterized; some of them were active at acid pH and others at neutral and alkaline pH. Leucocytes and alveolar macrophages had proteolygic activity for hemoglobin, fibrinogen, collagen and elastin. Using synthetic substrates, several enzymes were characterized: arylamidase, aminopeptidase, carboxypeptidases A and B and cathepsins A and C. The enzymatic activities were much higher in alveolar macrophages than in leucocytes.

Animals↗
PubMed1976

Purification by preparative electrophoresis and characterization of histone H2B from rat chloroleukaemia.

Highly purified histone H2B from rat chloroleukaemia has been isolated by preparative electrophoresis at pH 2.7 in polyacrylamide slab gel, using the fraction F2b of Johns (Johns E. W. (1964) Biochem, J. 92, 55-59) as starting material. This histone was characterized by amino acid analysis and end groups determination. Comparative studies with homologous calf thymus histone show similarity of the amino acid compositions and of the amino terminal groups. the carboxyl terminal sequence presents two conservative substitutions.

Amino Acid Sequence↗
PubMed1976

[Properties of histones on hydrophobic chromatography].

The hydrophobic chromatography on alkylated Sepharose allows to separate the histones into three groups which exhibit an increasing affinity for the support HI less than H2A-H2B less than H3-H4. In this fractionation procedure, the behaviour of the histones taken separately or pair-associated, is discussed in relation with the ability of these proteins to complex each other in vitro and in vivo.

Adsorption↗
PubMed1976

Sulphitolysis in keratinolysi. Biochemical proof.

The presence of S-sulphocysteine in filtrates of the dermatophyte Keratinomyces ajelloi growing on human hair in a culture medium buffered by pH 7-4 by phosphates was demonstrated by means of ion exchange chromatography techniques. S-sulphocysteine being destroyed during acidic hydrolysis was identified after enzymic hyrolysis of dialyzed and lyophilized filtrates. This result indicates that sulphitolysis occurs during kerationlysis performed by K. ajelloi. As thiosulphuric esters were shown present in hair perforations made by Microsporum gypseum, we think sulphitolysis is a common mechanism developed by dermatophytes to attack keratin.

Culture Media↗
PubMed1976

[Treatment of bronchial hypersecretion. Demonstration of polyanionic mucins-eprazinone interactions].

The study of therapeutical agents for "mucolysis" enables a classification of these drugs from their mode of action at the trachea-bronchial level (pharmacodynamic agents, enzymes, reducers, mucoregulation). The affinity of a piperazine derivative, eprazinone, for polyanionic bronchial mucins, was shown in vitro by spectrophotometry. Because of this property, eprazinone (Mucitux) might modify the fibrillar structure of bronchial mucus. This mode of action would differentiate this treatment from the mucolytic agents used today clinically.

Bronchi↗
PubMed1975

Guine pig liver L-asparaginase. Separation, purification, and intracellular localisation of two distinct enzymatic activities.

Two distinct L-asparaginase (EC 3.5.1.1) activities were detected in guinea pig liver: Asparaginase 1 and Asparaginase 2. Asparaginase 1 has been purified 272 fold from the crude homogenate; its molecular weight was evaluated by gel filtration to be about 150 000. The purified preparation was shown to be homogeneous by cellulose acetate strip and polyacrylamide disc-gel electrophoresis. Asparaginase 2 has been purified 63.5 fold from the crude homogenate. Its molecular weight was evaluated by gel filtration to be about 21 500. Cellulose acetate strip electrophoresis demonstrated two bands, one of which corresponded to Asparaginase 1 and the other to Asparaginase 2. Cellular fractionation in the ultracentrifuge, showed Asparaginase 1 to be present only in the cytosol fraction. Asparaginase 2 which was unstable at 105 000 X g seemed mostly localized in the mitochondria and secondarily in the cytoplasmic fraction.

Animals↗
PubMed1975

[Endo beta-N-acetylglucosaminidase in human liver].

Endo beta-N-acetylglucosaminidase activity was found in a alpha-L-fucosidase preparation purified from human liver homogenates, using glycopeptides from human parotid glycoprotein as a substrate. An oligosaccharide was purified and after reduction N-acetylglucosaminitol was shown by paper chromatography. Thus, the specificity and the significance of this endoglycosidase in glycoprotein catabolism are discussed.

Acetylglucosamine↗