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Biomedical subjects

S Stein

Publications and source records attributed to S Stein.

At least 127 records · Page 7Linked to original sources
PubMed1987

Active site of human liver aldehyde dehydrogenase.

Bromoacetophenone (2-bromo-1-phenylethanone) functions as an affinity reagent for human aldehyde dehydrogenase (EC 1.2.1.3) and has been found specifically to label a unique tryptic peptide in the enzyme. Amino-terminal sequence analysis of the labeled peptide after purification by two different procedures revealed the following sequence: Val-Thr-Leu-Glu-Leu-Gly-Gly-Lys. Radioactivity was found to be associated with the glutamate residue, which was identified as Glu-268 by reference to the known amino acid sequence. This paper constitutes the first identification of an active site of aldehyde dehydrogenase.

Acetophenones↗
PubMed1987

Gas-phase hydrolysis of proteins and peptides.

A simplified gas-phase hydrolysis procedure for proteins and peptides is described. The apparatus consists of a glass vacuum desiccator, a ceramic plate, and a Teflon ring. The method was shown to give reproducible compositions for hydrolysis of human serum albumin and microanalysis of alpha-melanocyte stimulating hormone including the quantitation of as little as one residue of tryptophan. It minimizes sample handling and allows for the simultaneous hydrolysis of a large number of samples.

Amino Acids↗
PubMed1987

Purified membrane and soluble folate binding proteins from cultured KB cells have similar amino acid compositions and molecular weights but differ in fatty acid acylation.

A membrane-associated folate binding protein (FBP) and a soluble FBP, which is released into the culture medium, have been purified from human KB cells using affinity chromatography. By NaDodSO4/PAGE, both proteins have an apparent Mr of approximately 42,000. However, in the presence of Triton X-100, the soluble FBP eluted from a Sephadex G-150 column with an apparent Mr of approximately 40,000 (similar to NaDodSO4/PAGE) but the membrane-associated FBP eluted with an apparent Mr of approximately 160,000, indicating that this species contains a hydrophobic domain that interacts with the detergent micelles. The amino acid compositions of both forms of FBP were similar, especially with respect to the apolar amino acids. In addition, the 18 amino acids at the amino termini of both proteins were identical. The membrane FBP, following delipidation with chloroform/methanol, contained 7.1 mol of fatty acid per mol of protein, of which 4.7 mol was amide-linked and 2.4 mol was ester-linked. The soluble FBP contained only 0.05 mol of fatty acid per mol of protein. These studies indicate that the membrane FBP of KB cells contains covalently bound fatty acids that may serve to anchor the protein in the cell membrane.

Acylation↗
PubMed1987

Patients and staff assess social climate of different quality nursing homes.

Three hundred and one patients and 231 nursing staff from 10 community nursing homes (categories from good to poor by independent judges) rated a 63-item scale assessing social climate along seven dimensions: cohesion, conflict, independence, self-exploration, organization, resident influence, and physical comfort. Regardless of quality of homes, mean ratings by staff were more favorable (p less than 0.001 using multivariate analysis of variance) than patient ratings on four of the seven factors. When staff attitudes were compared by quality of homes, less favorable staff ratings were found for cohesion, independence, and self-exploration in poorer quality homes. Patient responses were significantly less favorable on five of seven dimensions in poorer quality homes. In summary, nursing home patients react more negatively to their institutional environments than do staff, and though poorer institutional quality does correspond to less favorable ratings by staff and patients, it is still the patient group that reacts in a more negative manner.

Adult↗
PubMed1986

Purification and molecular characterization of human transcobalamin II.

Transcobalamin II (TCII) has been purified from Cohn fraction III of human plasma by batchwise binding to and then elution from carboxymethyl-Sephadex, affinity chromatography using photo-labile aminopropyl cobalamin coupled to activated Sephacryl S-200, and finally chromatography through carboxymethyl cellulose. The yield was approximately 80%. The addition of protease inhibitors in all steps of the purification procedure and extensive washing of the carboxymethyl-Sephadex prior to eluting the TCII minimized degradation of the protein and the final preparation of holo-TCII contained 1 mol of cobalamin/mol of protein. A single polypeptide of 43,000 daltons was obtained by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The NH2-terminal 19 amino acids have been determined for human TCII. 12 of the amino acids are homologous with rabbit TCII and six are homologous with human R-binder, but there is no homology with human intrinsic factor.

Amino Acid Sequence↗
PubMed1986

The primary structure of monkey pituitary growth hormone.

Monkey growth hormone (MGH) has been purified by reverse-phase high-performance liquid chromatography (HPLC). Tryptic digests of MGH were separated by HPLC and paper electrophoresis. From amino acid composition, from NH2-terminal residue and sequence analyses of these tryptic peptides, and from their alignment with those of human growth hormone, the primary structure of MGH was proposed. There are only four residues which are different in these two growth hormone molecules.

Amino Acid Sequence↗
PubMed1986

Human prothymosin alpha: amino acid sequence and immunologic properties.

Prothymosin alpha has been purified from human thymus and its amino acid sequence determined, except for a 15 amino acid segment including 10 glutamyl residues near the middle of the molecule. Like prothymosin alpha from rat thymus [A. A. Haritos, R. Blacher, S. Stein, J. Caldarella, and B. L. Horecker (1985) Proc. Natl. Acad. Sci. USA 82, 343-346], human prothymosin contains the thymosin alpha 1 sequence at its NH2-terminus. It contains a total of 109-110 residues compared to 111-112 for rat prothymosin alpha, with deletions corresponding to positions Gln39 and Lys108 of the rat polypeptide. Human prothymosin alpha also differs from rat prothymosin alpha at positions corresponding to residues 87, 92, and 102 of the latter, with substitutions of alanine for proline, alanine for valine, and aspartic acid for glutamic acid, respectively. Human prothymosin is significantly less active than rat prothymosin in protecting mice against infection with Candida albicans and in stimulating release in vivo of migration inhibitory factor. Thus, the differences in amino acid sequences, present mainly the COOH-terminal half of the polypeptides, may determine species specificity in biological properties.

Amino Acid Sequence↗
PubMed1986

Dominantly inherited craniodiaphyseal dysplasia: a new craniotubular dysplasia.

We describe a mother and her male infant affected with a craniotubular dysplasia characterized by severe craniofacial hyperostosis and sclerosis with obliteration of paranasal sinuses and foramina of the skull base. Subsequent severe bilateral hearing loss and facial diplegia with relative sparing of the optic nerves were noted. The long bones show extreme asymmetric hyperostosis and sclerosis of the diaphyses and evidence of a modelling defect in the metaphyses. The spine, ribs, clavicles, and pelvis all show some degree of sclerosis and defective modelling, but are less severely involved. According to the definition by Gorlin, this disorder would best be classified as craniodiaphyseal dysplasia. Distinguishing features in these two patients as contrasted to previously described cases include a greater degree of hyperostosis and sclerosis than that described for other patients with craniodiaphyseal dysplasia, apparent dominant transmission, and significant metaphyseal involvement.

Adult↗
PubMed1985

Characterization of recombinant human interleukin-2 with micromethods.

Highly purified recombinant human interleukin-2, expressed in Escherichia coli, was analyzed by micromethods. N-Terminal sequence analysis showed that methionine at position 0 was found in 90% of the molecules and not completely removed in post-ribosomal processing. A complete peptide map of the reduced and S-carboxymethylated protein was obtained by high-performance liquid chromatography after tryptic digestion, and the fragments were identified by amino acid analysis and automated Edman sequence analysis. Using a double-label S-carboxymethylation procedure, it was determined that there is a disulfide linkage between the cysteine residues at positions 58 and 105. The third cysteine residue at position 125 was found to be present as the free sulfhydryl.

Amino Acid Sequence↗
PubMed1985

Reasons for smoking among extremely heavy smokers.

Four factors describing reasons for smoking were identified in 200 heavy smokers. When these four factor scores were correlated with other variables, the Addictive/Habitual Needs factor correlated most often with increased use of tobacco, alcohol, and coffee. The Pleasure factor was associated with obesity and the Stress Reaction factor with more perceived stress. The Stress Reaction factor was consistently correlated with more unfavorable ratings on psychological adjustment. Persons who smoked to alleviate stress or for addictive/habitual needs had tried to stop more often, whereas those who smoked for pleasure had little motivation to stop smoking. Findings suggest that there are individual differences in reasons for smoking among extremely heavy smokers and that these need to be taken into account in trying to help such individuals.

Adult↗
PubMed1985

Primary structure of rat thymus prothymosin alpha.

The primary structure of prothymosin alpha from rat thymus, containing 113 amino acid residues, is reported as follows: (formula; see text) The sequence of the first 28 amino acids at the NH2 terminus is identical to that of calf thymosin alpha 1. The dicarboxylic amino acids, which account for nearly half of the total residues in prothymosin alpha, are largely clustered in the central portion of the polypeptide chain. The polypeptide contains no aromatic or sulfur-containing amino acids. A computer analysis of the three-dimensional structure based on the primary sequence suggests that the molecule is composed of at least five alpha-helical regions interrupted by one short extended chain and three short random coils.

Amino Acid Sequence↗
PubMed1985

Parathymosin alpha: a peptide from rat tissues with structural homology to prothymosin alpha.

A peptide, parathymosin alpha, containing approximately equal to 105 amino acid residues, has been isolated from rat thymus, and the sequence of the first 30 residues at the NH2 terminus has been determined. In this region, it shows 43% structural identity with thymosin alpha 1 and prothymosin alpha. The common sequences do not include residues 2-9, which accounts for the poor reactivity of parathymosin alpha with an antibody directed against this epitope in thymosin alpha 1. Parathymosin alpha appears to modulate the action of prothymosin alpha in protecting sensitive strains of mice against opportunistic infection with Candida albicans.

Adjuvants, Immunologic↗
PubMed1985

Geriatric sweet tooth. A problem with tricyclics.

Ninety-three consecutive outpatients receiving tricyclic antidepressants for at least one month were asked about medication side effects, including excessive appetite and craving for sweets. Prevalence of these side effects and their relationship (Pearson r) to type of medication, dosage, patient characteristics, diagnoses, weight gain, and clinical improvement were examined. More than one-third (38%) reported excessive appetite, 34% had a craving for sweets, and about one-half (48%) had either one or the other of these reactions. These adverse side effects were related significantly to weight gain (P less than .001) and a higher dose of medication, but not to clinical improvement. Clinical improvement was in the moderate-to-good range but was not related to medication dose. Because increasing degrees of overweight can pose serious health risks, especially for the elderly, it is critical for future research to examine ways of maintaining therapeutic benefit while minimizing food craving side effects. Methods of dealing with these issues clinically are suggested.

Age Factors↗