Characterization of Gastrointestinal Amino Acid and Peptide Transport Proteins and the Utilization of Peptides as Amino Acid Substrates by Cultured Cells (Myogenic and Mammary) and Mammary Tissue Explants

Intermediate filaments (IF) isolated from a variety of cultured cells, conventionally described as fibroblasts, are composed predominantely of proteins of molecular weights of 54,000 and/or 55,000. Less than 15% of the protein found in native IF preparations from these cells is composed of three to four polypeptides of molecular weights 60,000-70,000. We have investigated some biochemical and immunological properties of these proteins isolated from BHK-21 and mouse 3T3 cells. They are capable of forming paracrystals that exhibit a light/dark banding pattern when negatively stained with uranyl acetate. The dark bands are composed of longitudinally aligned approximately 2-nm-diam filaments. The center-to-center spacing between either dark or light bands is 37-40 nm. These dimensions are consistent with the secondary structure of IF polypeptides and suggest that the dark bands represent lateral alignment of alpha-helical coiled-coil domains. Immunoblotting, secondary structure, as well as amino acid composition data indicate that the 60,000-70,000-mol-wt paracrystal polypeptides are similar to keratin. Thus, polypeptides with biochemical and immunological properties of epidermal keratin are present in cells normally considered to be fibroblasts.

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Isolation and characterization of S. cerevisiae mutants deficient in amino acid-inducible peptide transport

Current Genetics ◽

10.1007/bf00334772 ◽

1991 ◽

Vol 20 (6) ◽

pp. 457-463 ◽

Cited By ~ 28

Author(s):

Michael D. Island ◽

Jack R. Perry ◽

Fred Naider ◽

Jeffrey M. Becker

Keyword(s):

Amino Acid ◽

Peptide Transport ◽

Isolation And Characterization

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PURIFICATION AND PARTIAL CHEMICAL CHARACTERIZATION OF SHEEP NEUROPHYSIN

Acta Endocrinologica ◽

10.1530/acta.0.0740226 ◽

1973 ◽

Vol 74 (2) ◽

pp. 226-236 ◽

Cited By ~ 6

Author(s):

Michel Chrétien ◽

Claude Gilardeau

Keyword(s):

Amino Acid ◽

Polyacrylamide Gel Electrophoresis ◽

Chemical Characterization ◽

Terminal Amino Acid ◽

Amino Acid Determination ◽

Pituitary Glands ◽

Terminal Amino ◽

Partial Chemical ◽

Acid Determination

ABSTRACT A protein isolated from ovine pituitary glands has been purified, and its homogeneity assessed by NH2- and COOH-terminal amino acid determination, ultracentrifugation studies, and polyacrylamide gel electrophoresis after carboxymethylation. Its chemical and immunochemical properties are closely similar to those of beef and pork neurophysins, less similar to those of human neurophysins. It contains no tryptophan (like other neurophysins) or histidine (like all except bovine neurophysin-I and human neurophysins). It has alanine at the NH2-terminus and valine at the COOH-terminus. Its amino acid composition is similar to, but not identical with those of porcine and bovine neurophysins.

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