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R Cardinaud

Publications and source records attributed to R Cardinaud.

33 records · Page 2Linked to original sources
PubMed1979

[Fragmentation of myosin A-1 light chain of fast muscle by trypsin].

Limited proteolysis of myosin by such proteolytic enzymes as trypsin, chymotrypsin or papain produces typical fragmentation of its heavy chain. Presently evidence is given that trypsin treatment cleaves the alkali light chain A-1 (20,700 dalton) to a shorter (ca 20,000 dalton) chain. The two "essential" thiols (SH-1 and 2) of moysin were alkylated with 17-C-N-ethylmaleimide and a non-negligible amount of radioactivity was also found in the two alkali light chains. Using the specific radioactivity of alkali light chain A-1 it was possible to identify it among heavy chain fragmentation products. The molecular weight of the newly formed A-1 indicates that limited tryptic cleavage of this A-1 confers on it a closer similarity with alkali light chain A-2.

Animals↗
PubMed1979

Proteolytic fragmentation of myosin: location of SH-1 and SH-2 thiols.

The heavy chain fragmentation pattern of native myosin when digested by proteolytic enzymes is influenced by such conditions as the nature of the proteolytic agent, ionic strength and presence or absence of divalent cations. HMM and S-1 produced by digestion of 14CNEM-labelled myosin under various conditions were analyzed by sodium dodecyl-sulfate polyacrylamide gel electrophoresis. Purified samples of these species were digested under controlled conditions by chymotrypsin and trypsin and a comparison of the observed heavy chain fragmentation patterns led to a sequential arrangement of the proteolytic fragments. The main features of this arrangement are the following: a 21K molecular weight tryptic peptide is found at the N-terminal side of myosin heavy chain. Adjacent to it is a 48K peptide, then a 19.5K peptide containing the two SH-1 and SH-2 thiols. These three peptides constitute the heavy chain of S-1. Adjacent to this S-1 heavy chain is a tryptic (and also chymotryptic) 40K peptide. The rest of the HMM heavy chain on the C-terminus is a sequence susceptible to both chymotrypsin and trypsin attack yielding an undefined number of small peptides.

Animals↗
PubMed1976

Deoxyribosyl transfer catalysis with trans-N-deoxyribosylase. Kinetic study of purine(pyrimidine) to pyrimidine(purine) trans-N-deoxyribosylase.

Kinetic studies were carried out in order to investigate the enzymic mechanism of a 215-fold-purified purine(pyrimidine) nucleoside: purine(pyrimidine) deoxyribosyl transferase fraction from Lactobacillus helveticus. A variety of natural deoxyribonucleosides and bases were used as substrates. Initial velocity, product inhibition and isotopic exchange studies are consistent with a ping-pong bi-bi mechanism. The kinetic parameters are used to show that this fraction is free from any contamination by a specific purine nucleoside: purine deoxyribosyl transferase also found in the same strain of L. helveticus.

Adenine↗
PubMed1975

Trans-N-deoxyribosylase: purification by affinity chromatography and characterization.

trans-N-Deoxyribosylase (EC 2.4.2.6) is usually considered as a single protein catalyzing indifferently the transfer of the deoxyribosyl moiety to and from a purine or a pyrimidine base. Affinity chromatography of an extract from Lactobacillus helveticus with two types of ligands allowed the separation and purification of two distinct trans-N-deoxyribosylases. One catalyzes specifically the deoxyribosyl transfer to and from purine bases exclusively: trans-N-deoxyribosylase-I, the other catalyzes the transfer to and from pyrimidine and purine bases: trans-N-deoxyribosylase-II. A Tris inhibition study showed a markedly different susceptibility of the two enzymes. Preliminary results indicate that the purine-specific enzyme is a polymeric enzyme of molecular weight 86 000 (+/- 4000).

Chromatography, Affinity↗
PubMed1975

Trans-N-deoxyribosylase: substrate specificity studies. Purine bases as acceptors.

A series of purine bases and analogues were tested as substrates for trans-N-deoxyribosylase (EC 2.4.2.6). It was observed that the pyrimidine ring and its substituents on positions 1, 2 and 6, are of minor importance. On the other hand only a few modifications are tolerated on the imidazole moiety, as follows. 1. A tautomeric proton must be present on the imidazole ring. The "usual" shift is between position 9 and 7. 2. The position of the tautomeric proton governs the site of substitution. 3. For steric reasons no substituent is allowed on position 8.

Deoxyribonucleosides↗