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P Lehky

Publications and source records attributed to P Lehky.

8 recordsLinked to original sources
PubMed1979

Perch muscle parvalbumin: general characterization and magnesium-binding properties.

1. Parvalbumin exists in two major forms, amounting to 2.5 and 3.2 g per kg of fresh muscle. 2. The composition divergence index between both forms, calculated from their amino acid composition, indicates 81% sequence identity; however both isoparvalbumins are immunologically distinct. 3. Beside Ca2+, perch parvalbumin binds 2 g atoms Mg2+ per mol with a dissociation constant of 10(-5) M. 4. Determination of the affinity for magnesium is of particular importance as there are indications that, in vivo, parvalbumin can remain in the Mg2+-state during the contraction-relaxation cycle instead of switching from the Ca2+-to the Mg2+-state and vice versa.

Animals↗
PubMed1977

Comparative properties of vertebrate parvalbumins.

Pure parvalbumins isolated from turtle, chicken, and rabbit white skeletal muscle have been characterized in terms of their physical, chemical, and immunological properties. As for the parvalbumins of most fish and amphibians, they have sedimentation constants S20,w of approximately 1.45 +/- 0.25 S and molecular weights of approximately 12,000, with little or no evidence for aggregation. They contain no tryptophan, at most one tyrosine, and a high proportion of phenylalanine, resulting in characteristic absorption spectra. All three parvalbumins contain 2 g atoms of calcium/mol bound with a KDiss less than or equal to 10(-6) M. Complete removal of calcium can be achieved by treatment with EDTA and EGTA or by a purified preparation of fragmented sarcoplasmic reticulum. By a direct analytical procedure, the concentration of parvalbumins in white skeletal muscle from the turtle, chicken, and rabbit was estimated at approximately 9 to 11, 0.2 to 0.4, and 0.6 to 1.1 g/kg, respectively. No parvalbumin or immunologically cross-reacting material could be detected in chicken white breast muscle, and very little was found in rabbit red muscle. All three proteins are immunologically distinct. A "minor" isoparvalbumin (approximately 2% of the major component) was found in turtle muscle only.

Amino Acids↗
PubMed1976

On the subunit structure of particulate aminopeptidase from pig kidney.

Solubilization of particulate aminopeptidase (EC 3.4.11.2) from pig kidney with Triton X-100 yields an aggregate (mol. wt. approx. 10(6)) that decomposes into "free" aminopeptidase (mol. wt. 280 000) either upon autolysis at pH 5 or after exposure to trypsin. Both procedures yield free enzymes that are identical with respect to electrophoretic mobility, enzymatic activity and zinc content. After dissociation, the enzyme resulting from autolysis yields a single subunit of 140 000 molecular weight while the trypsin-treated enzyme produces three fragments (140 000, 95 000 and 48 000 mol. wt.). As the aggregate is formed by subunits 10 000 daltons heavier than those of the free enzyme, the existence of a hydrophobic portion anchoring the enzyme to the membrane might be postulated. Reactivation experiments carried out on the three purified fragments of urea-denatured aminopeptidase show that the 140 000 molecular weight subunit is the only one able to yield an active enzyme (after spontaneous dimerization). It can be concluded that the smaller fragments are artefacts resulting from trypsin degradation during purification.

Aminopeptidases↗