Physicochemical characterization of psychosine by 1H nuclear magnetic resonance and electron microscopy

L. Őrfi, Cynthia K. Larive, Steven M. LeVine

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Krabbe's disease is an autosomal recessive disease that affects the lysosomal enzyme galactosylceramidase. The storage of one of its substrates, psychosine (β-galactosyl-sphingosine), is thought to be responsible for the induction of pathological changes. Psychosine has a free amine group which is necessary for the mediation of its toxic effects. In the present study, the physicochemical properties of psychosine were investigated. Nuclear magnetic resonance (NMR) detected pH titration was used to determine that the amine group had a pKa of 7.18 ± 0.05. Pulsed-field gradient NMR spectroscopy was used to determine that the diffusion coefficient of 2.8 mM psychosine in D2O at pD 4.46 or 7.04 is 1.16 ± 0.02 x 10-10 m2/s or 0.77 ± 0.02 x 10- 10 m2/s, respectively. Negative staining electron microscopy (EM) studios of acidic and neutral solutions of psychosine also were performed. At pH 4.5, spherical structures were formed, which were relatively stable between 3, 120, and 216 h following preparation; the diameter ranged from ~14 nm at the earliest time point to ~18 nm at the last time point. The critical micelle concentration (CMC) was 1.26 mM at pH 4.0. At pH 7.1, the structures changed from spherical structures with a diameter of 15-23 nm, at the earliest time point, to a heterogeneous population of structures ranging from spherical structures, with a diameter of only a few nm, to irregularly shaped oblong structures that had one or more dimensions exceeding 100 nm. The NMR and EM data indicate that the deprotonation of the amine group causes psychosine to form aggregates that are unstable, which prevents a determination of the CMC at a neutral pH. These data indicate that molecular interactions of psychosine at the acidic pH of the lysosome, where it is normally digested; are more orderly than those at the pH of the cytoplasm or extracellular space where psychosine goes during disease.

Original languageEnglish
Pages (from-to)1035-1040
Number of pages6
JournalLipids
Volume32
Issue number10
DOIs
Publication statusPublished - Oct 1997

Fingerprint

Psychosine
Electron microscopy
nuclear magnetic resonance spectroscopy
electron microscopy
Electron Microscopy
Magnetic Resonance Spectroscopy
Nuclear magnetic resonance
amines
Amines
micelles
Critical micelle concentration
Micelles
Galactosylceramidase
sphingosine
Globoid Cell Leukodystrophy
extracellular space
Negative Staining
lysosomes
Deprotonation
Sphingosine

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Food Science
  • Biochemistry

Cite this

Physicochemical characterization of psychosine by 1H nuclear magnetic resonance and electron microscopy. / Őrfi, L.; Larive, Cynthia K.; LeVine, Steven M.

In: Lipids, Vol. 32, No. 10, 10.1997, p. 1035-1040.

Research output: Contribution to journalArticle

Őrfi, L. ; Larive, Cynthia K. ; LeVine, Steven M. / Physicochemical characterization of psychosine by 1H nuclear magnetic resonance and electron microscopy. In: Lipids. 1997 ; Vol. 32, No. 10. pp. 1035-1040.
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