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Biomedical subjects

V J Hruby

Publications and source records attributed to V J Hruby.

At least 451 records · Page 25Linked to original sources
PubMed1978

A reassessment of structure-function relationships in glucagon. Glucagon1-21 is a full agonist.

Glucagon1-21 has been prepared by treating native glucagon with carboxypeptidase A. Purified glucagon1-21 did not contain detectable methionine (less than 0.001 residue/mol) and the activity of the compound did not change after treatment with cyanogen bromide as has been shown with native glucagon. Glucagon1-21 stimulates hepatic adenylate cyclase activity to the same extent as native glucagon but with 0.1% the potency. Glucagon1-21 also displayed 0.1% the binding affinity of native glucagon to the glucagon receptor in hepatic membranes. Glucagon22-29 alone or in combination with glucagon1-21 did not activate adenylate cyclase or displase 125I-glucagon from its receptor. The finding that glucagon1-21 is a full agonist on adenylate cyclase is discussed in relation to the structure-function relationships required for the biological action of glucagon.

Adenylyl Cyclases↗
PubMed1978

Conformation of oxytocin studied by laser Raman spectroscopy.

The peptide backbone conformation and salient structural details of oxytocin were examined by laser Raman spectroscopy. Spectra were obtained in the solid phase, water, 2H2O, and dimethyl sulfoxide solutions. A distinct Amide I band was obtained at 1663 cm-1 for aqueous and deuterated samples and 1666 cm-1 for the solid sample. A relatively high frequency Amide III band at 1260 cm-1 was obtained. It is concluded that these Amide I and III bands arise from the "beta-turn"-like conformation of oxytocin. The tyrosine side chain, according to the I850 cm-1/I830 cm-1 intensity ratio, is exposed to the solvent. The S-S stretching vibration at 512 cm-1 indicates the conformation of C-C-S-S-C-C in the disulfide bridge of oxytocin in the ring is gauche-gauche-gauche.

Lasers↗
PubMed1978

Location by paper chromatography of compensatory ovarian hypertrophy (COH) inhibiting activity in acetic acid extracts from bovine pineals.

Acetic acid extracts of bovine pineals and cerebral cortex were separated on Sephadex G-25 columns. Subsequently two low molecular weight fractions, F2 and F3, were ultrafiltered through the membranes UM2 and UM05. The UM05 residues were gel filtered on Sephadex G-15 columns or chromatographed on Dowex W50-X4 columns. Fractions from these columns were tested and those which showed COH-inhibiting activity were separated by preparative paper chromatography in different solvents. The absorption spectra of those fractions were recorded and tested for COH-inhibiting activity were separated by preparative paper chromatography in different solvents. The absorption spectra of those fractions were recorded and tested for COH-inhibition. By these methods, a COH-inhibitor was localized in three different solvents. Some active paper chromatography fractions were studied in high pressure, reverse phase, liquid chromatography. This latter method showed that the active fractions obtained by paper chromatography contain several orthophthlaldehyde (OPT) positive compounds. Key words: acetic acid, bovine pineal extracts, compensatory ovarian hypertrophy (COH), paper chromatography, high pressure, reverse phase, liquid chromatography.

Acetates↗
PubMed1978

Reverse phase high pressure liquid chromatography for the separation of peptide hormone diastereoisomers.

Diastereoisomers of specifically labeled oxytocin derivatives were resolved using reverse phase high pressure liquid chromatography. The peptides [1-hemi-DL-[alpha-2H]cystine]oxytocin, [6-hemi-DL-[alpha-2H]cystine]oxytocin, [2-DL-[alpha-2H]tyrosine]oxytocin and[8-DL-[2-13C]leucine]oxytocin were readily separated using the conditions described. The diastereoisomers of the oxytocin analog [3-DL-[2-13C]leucine]oxytocin also demonstrated baseline resolution under the same conditions. The procedure offers the investigator a rapid method for screening synthetic oxytocin peptides for undesirable diastereoisomeric by-products.

Chromatography, High Pressure Liquid↗
PubMed1977

Relative conformational rigidity in oxytocin and (1-penicillamine)-oxytocin: a proposal for the relationship of conformational flexibility to peptide hormone agonism and antagonism.

A comparative study of the proton and carbon-13 nuclear magnetic resonance spectral parameters of the peptide hormone oxytocin and of its competitive inhibitor [1-L-penicillamine]oxytocin has been made, and the results analyzed in terms of comparative conformational and dynamic properties. The results indicate that oxytocin has a flexible conformation, while [1-L-penicillamine]oxytocin has a more restricted conformation. The results provide a framework for understanding the mechanism of peptide hormone agonism and antagonism for these compounds, and an approach for understanding some features of the interaction of the hormone and related compounds with their receptor.

Binding Sites↗