𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Effects of pH and temperature on cardioactive polypeptides from sea anemones: A 1H-nmr study

✍ Scribed by Paul R. Gooley; John W. Blunt; Laszlo Beress; Raymond S. Norton

Publisher
Wiley (John Wiley & Sons)
Year
1988
Tongue
English
Weight
866 KB
Volume
27
Category
Article
ISSN
0006-3525

No coin nor oath required. For personal study only.

✦ Synopsis

The effects of pH and temperature on the 300-MHz 'H-nmr spectra of three cardioactive polypeptides from sea anemones, anthopleurin-A from Anthopleura zunthogrammicu (AP-A) and Ammonia sukutu toxins I and I1 (ATX I and 11), are described. AP-A and ATX I1 exhibit major spectral heterogeneity. Evidence from the pH and temperature studies and from high performance liquid chromatography indicates that this heterogeneity is conformational rather than chemical in origin. By contrast, purified isotoxins of ATX I show no evidence of conformational heterogeneity. The pKa values of most of the ionizable groups in these polypeptides are not strongly perturbed by interactions in the tertiary structure, with the exception of one of the Asp carboxylates, which has a pKa of 5 2 in AP-A and ATX I1 and 3.0 in ATX I. Protonation of this carboxylate, suggested to be Asp-9, leads to a conformational change in all three molecules. All three polypeptides are thermally stable, showing some conformational changes but not major unfolding at elevated temperatures.

📜 SIMILAR VOLUMES

Variable-temperature and pH studies of a
Variable-temperature and pH studies of a DNA minor groove binder, Hoechst 32985, by 1H NMR spectroscopy
✍ Keith J. Cross; Kevin J. Embrey; Murray Coles; Wendy Bicknell; David J. Craik 📂 Article 📅 1994 🏛 John Wiley and Sons 🌐 English ⚖ 772 KB

## Abstract ^1^H NMR spectra of the dipiperazine‐based DNA minor groove binding compound Hoechst 32985 indicate that at room temperature and low pH (2.90) a single conformation is detected. This is attributed to the form in which both piperazine rings are protonated at the __N__‐methyl and the bulk

Prilocaine–cyclodextrin–liposome: effect
Prilocaine–cyclodextrin–liposome: effect of pH variations on the encapsulation and topology of a ternary complex using 1H NMR
✍ Luís Fernando Cabeça; Isis Martins Figueiredo; Eneida de Paula; Anita Jocelyne M 📂 Article 📅 2011 🏛 John Wiley and Sons 🌐 English ⚖ 145 KB

## Abstract A better comprehension of the prilocaine (PLC)–β‐cyclodextrin (β‐CD) complex liberation to membranes was provided by studying the architectural supramolecular arrangements of PLC, β‐CD and egg phosphatidylcholine (EPC) liposomes, a membrane model. The topologies and possible interaction

A study of substituent effect on 1H and
A study of substituent effect on 1H and 13C nmr spectra of N- and C-substituted carbazoles
✍ Sergio M. Bonesi; Maria A. Ponce; Rosa Erra-Balsells 📂 Article 📅 2004 🏛 Journal of Heterocyclic Chemistry 🌐 English ⚖ 274 KB 👁 1 views

## Abstract ^1^H and ^13^C nmr spectra of several __N__‐ and C‐substituted carbazoles (Series 1, 2, 3 and 4) were measured. Correlations between chemical shifts and substituent constants show that these parameters describe properly the substituent effect on the nmr phenomena. Atomic charge densitie

A study of substituent effect on 1H and
A study of substituent effect on 1H and 13C NMR spectra of mono, di and poly substituted carbazoles
✍ Sergio M. Bonesi; Maria A. Ponce; Rosa Erra-Balsells 📂 Article 📅 2005 🏛 Journal of Heterocyclic Chemistry 🌐 English ⚖ 122 KB 👁 1 views

## Abstract ^1^H and ^13^C NMR spectra of several substituted carbazoles (Series 1, 2, 3, 4 and 5) were measured. Substituent chemical shifts (SCS's) and Lynch correlations of ^1^H and ^13^C nuclei were calculated and the substituent effect on the NMR phenomena was determined. Atomic charge densiti