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G Liguri

Publications and source records attributed to G Liguri.

51 records · Page 3Linked to original sources
PubMed1985

Rabbit skeletal muscle acylphosphatase: the amino acid sequence of form Ra1.

Acylphosphatase was purified from rabbit skeletal muscle by a procedure involving an affinity chromatography step on immunoadsorbent and subsequent ion-exchange chromatography. Three molecular forms with acylphosphatase activity, named Ra1, Ra2, and Ra3, were purified and characterized with respect to molecular weight, amino acid composition, and main kinetic parameters. The amino acid sequence of Ra1 is given in the present paper. The Ra1 form consists of a single polypeptide chain of 98 amino acid residues and contains only one cysteine residue at position 21 that is S-S bound to glutathione. The polypeptide chain has an acetyl group blocking the NH2 terminus. Ra1, Ra2, and Ra3 are compared with the corresponding molecular forms isolated from skeletal muscle of horse and turkey.

Acid Anhydride Hydrolases↗
PubMed1985

Acylphosphatase from human skeletal muscle: purification, some properties and levels in normal and myopathic muscles.

Human skeletal muscle acylphosphatase was purified by immunoaffinity chromatography using anti-horse muscle acylphosphatase antibodies. The three forms of the enzyme present in human muscle are very similar to those found in muscles of other animal species. The two main forms, Hu 1 and Hu 3, were also characterized with respect to molecular weight and some kinetic properties. Levels of acylphosphatase activity were measured in specimens of muscle from normals and from patients with various forms of muscular dystrophies and other myopathies. Acylphosphatase activity appears to be lower in all myopathic forms considered than in controls, and seems to be correlated with percentage of Ca2+ activation of (Ca2+ + Mg2+)-ATPase.

Acid Anhydride Hydrolases↗
PubMed1984

Studies on synthesis and degradation rates and some molecular properties of guinea-pig muscle acylphosphatase.

Acylphosphatase (acylphosphate phosphohydrolase, EC 3.6.1.7) was purified from guinea-pig muscle by a procedure involving immuno-affinity chromatography and a subsequent ion-exchange chromatography. This purification technique gave an overall yield of about 60% and permitted the isolation of three molecular forms with acylphosphatase activity, with a distribution greatly resembling those found in horse and turkey muscle. The main form appears to be very similar to the corresponding form in horse and turkey muscle, as indicated by amino acid composition, end-group analysis, the presence of glutathione as a mixed disulphide in almost the same stoichiometric ratio and kinetic analysis. From turnover data, the main form of acylphosphatase in guinea-pig muscle exhibits a degradation constant of 0.10 day-1, corresponding to a half-life of 6.8 days. These values are very close to those found for muscle total soluble proteins.

Acid Anhydride Hydrolases↗
PubMed1984

Human skeletal muscle acylphosphatase: the primary structure.

Human skeletal muscle acylphosphatase, purified by a technique based on affinity chromatography on immunoadsorbent, has been sequenced completely using tryptic and peptic peptide series, prepared by reverse-phase high-pressure liquid chromatography. The sequence analysis was carried out on all the isolated tryptic peptides using a manual Edman degradation technique and time-course analysis of the released amino acids by carboxypeptidase A. The enzyme is NH2-blocked and the blocking group has been identified by fast atom bombardment mass spectrometry.

Acid Anhydride Hydrolases↗
PubMed1983

The primary structure of turkey muscle acylphosphatase.

The complete primary structure of turkey muscle acylphosphatase has been determined. The sequence was derived from peptides obtained by digestion of the carboxymethylated protein with pepsin and thermolysin and by subdigestion of some of the cyanogen bromide fragments with trypsin and Staphylococcus aureus protease. Peptides were purified by preparative finger prints and/or preparative high-performance liquid chromatography. Sequencing of the various peptides was achieved by manual Edman degradation and by time-course analysis of amino acids released by carboxypeptidases. The amino-terminal blocking group (acetyl) was determined by fast atom bombardment mass spectrometry. This sequence was compared with that of horse muscle enzyme determined previously.

Acid Anhydride Hydrolases↗
PubMed1983

Affinity chromatographic purification of horse muscle acylphosphatase: evidence of the existence of multiple molecular forms.

Acylphosphatase was purified from horse muscle by a new procedure involving an affinity chromatography step and subsequent ion-exchange chromatography. This procedure was considerably milder than the preceding one, gave an overall yield of about 60% of activity and permitted isolation of three molecular forms with acylphosphatase activity. All these enzymatic forms are tightly bound to Sepharose 4B-linked anti-horse muscle acylphosphatase antibodies. Two of these forms (Ho1 and Ho3) are present in larger amounts: Ho1 corresponds to the enzyme purified according to the older procedure; this enzyme is a mixed disulfide between a main chain of 98 amino acid residues and glutathione. Ho2 differs from Ho1 only in the chemical nature of the molecule(s) S-S bound to the sole cysteine present at position 21 of the main chain. Ho3 is an S-S dimer of the main polypeptide chain. Ho1, Ho2, and Ho3 elicit very similar kinetic parameters in the presence of benzoylphosphate as a substrate.

Acid Anhydride Hydrolases↗
PubMed1982

Purification of horse muscle acylphosphatase antibodies by affinity chromatography.

Horse muscle acylphosphatase antibodies were obtained by immunizing rabbits with the highly purified antigen cross-linked with glutaraldehyde. Specific antibodies were purified from the immunoglobulin fraction by affinity chromatography using a matrix coupled with the pure antigen as immunoadsorbent. The purified antibodies were partially characterized by immunodiffusion and immunoprecipitin techniques. These antibodies could be used to study aspects of the muscle acylphosphatase structure, localization and other biological properties.

Acid Anhydride Hydrolases↗
PubMedDate not supplied

Horse heart acylphosphatase: purification and characterization.

The use of an affinity chromatography step performed with an immunoadsorbent consisting of anti-horse muscle acylphosphatase antibodies covalently linked to Sepharose 4B allowed us to purify horse heart acylphosphatase in a very rapid and efficient fashion. As in skeletal muscle, also in heart the enzyme is present as both a mixed disulfide with glutathione and a S-S dimer. The abundance of these forms in heart is quite lower than in skeletal muscle. The comparison of the molecular forms so purified with those obtained from horse skeletal muscle showed the same aminoacid composition, tryptic fingerprint, together with strictly similar apparent molecular weight and main kinetic parameters, supporting the conclusion that the acylphosphatase present in heart is the same enzyme as that purified from skeletal muscle.

Acid Anhydride Hydrolases↗
PubMedDate not supplied

Quantitative determination of acylphosphatase levels in horse tissues by enzyme-linked immunosorbent assay.

A non competitive enzyme-linked immunosorbent assay (ELISA) specific for horse muscle acylphosphatase (E.C. 3.6.1.7.) has been developed. The purified anti-acylphosphatase antibodies were immobilized by passive absorption to a solid-phase support and incubated with known and unknown amounts of antigen. The antibody-acylphosphatase complex was quantified using the same antibody conjugated to horseradish peroxidase. The assay yields positive reactions with as little as 0.05 ng of antigen, with intra- and interassay coefficients of variation of 5% and 7%, respectively. On the basis of this assay we developed a more sensitive test than the optical one, using benzoyl-phosphate as substrate, for acylphosphatase determination. By means of this test, the presence of the enzyme in horse tissue homogenates was evaluated under conditions in which the optical test failed to distinguish the acylphosphatase activity from that of other enzymes.

Acid Anhydride Hydrolases↗
PubMedDate not supplied

Turkey muscle acylphosphatase: purification and comparative studies.

Turkey muscle acylphosphatase is strongly bound to anti-(horse muscle acylphosphatase ) antibodies covalently linked to an agarose resin. This permits use of an affinity chromatography step in the purification, which increased the final yield and allowed us to isolate three different molecular forms of the enzyme. Form 1 is a mixed disulfide between the polypeptide chain and glutathione; form 3 is an S-S dimer of the polypeptide chain present in form 1, while form 2, present in a very low amount, consists of a polypeptide chain quite similar in aminoacid composition to that found in form 1. The three molecular forms show very similar kinetic parameters. The comparison of these molecular forms with those isolated from horse muscle showed similar kinetic properties but different structural features.

Acid Anhydride Hydrolases↗
PubMedDate not supplied

Purification, kinetic properties and primary structure of bovine erythrocyte acylphosphatase.

An erythrocyte isoenzyme of acylphosphatase was purified from bovine red cells. The protein was characterized as regards the kinetic parameters and amino acid sequence. A simple and rapid sequencing strategy, based on a few experiments, was used for reconstructing the primary structure of the enzyme, since the purification procedure gave a very low yield. The length of the polypeptide chain is 100 residues. Comparison with the analogous human isoenzyme indicates that the primary structure is about 90% conserved. The presence of two additional residues at the acetylated N-terminus confirms the hypervariability for this region found in other acylphosphatases.

Acid Anhydride Hydrolases↗