Dependence of rat liver CMP‐N‐acetylneuraminate:GM₁ sialyltransferase (SAT IV) activity on the ceramide composition of GM₁ ganglioside

Abstract

The dependence of CMP-N-acetylneuraminate:GMl sialyltransferase (SAT IV) activity of rat liver Golgi apparatus on GM1 ganglioside ceramide composition was evaluated. SAT IV activity was assayed on GMI molecular species carrying homogeneous ceramide moieties containing long chain bases of different length (18 or 20 C atoms) unsaturated or not, linked to 14:0, 16:0, 18:0 or 22:0 fatty acids. The results obtained in the presence of the detergent Triton CF-54, when enzyme and substrate are presumably part of the same supramolecular structure, show that either the long chain base or the fatty acid composition can affect enzyme activity. This feature was not displayed when GM1 was embedded in dipalmitoylphosphatidylcholine vesicles in the absence of detergent. Under the latter conditions, the enzyme was not sensitive to the lipid composition of GMI but to the gangliosidelphospholipid ratio in the vesicles. These results indicate for the first time that SAT IV is affected by the lipid composition of the substrate and strengthen the hypothesis that glycosyltransferases may contribute to control the cellular glycosphingolipid ceramide pattern.1~ ey words." Sialyltransferase; GM1 ; Ceramide [6,7]. Moreover, it has been shown that glycosyltransferases are able to recognize different molecular species of the substrate, providing a mechanism aiming to maintain the glycolipid ceramide pattern of a given tissue [8]. The present work was carried out in order to assess whether SAT IV differentially affects molecular species of the same substrate, namely GM1 ganglioside, carrying different, homogeneous, ceramide moieties.

Ganglioside lateralization in the brain of female rats

“…In general, most of the investigations concerning gangliosides take into account only their oligosaccharide moiety, even if several studies show that also the ceramide moiety changes throughout animal life (Ando and Yu, 1984;Palestini et al, 1990Palestini et al, , 1991b) and can play a relevant biological role (Masserini et al, 1988(Masserini et al, , 1989Palestini et al, 1991a;Pitto et al, 1996). For this reason, the LCB and the fatty acid composition of gangliosides in the two hemispheres were analyzed.…”

Changes of Free Long‐Chain Bases in Neuronal Cells During Differentiation and Aging in Culture

“…Thus, it has been suggested that a key role is played by the predetermined distribution of C 18-and C20-sphinganines that is related to the kinetic properties of the enzyme acyl-CoA:serine acyltransferase (Chigorno et al,i994). Moreover, concerning the biosynthesis of glycosphingolipids, it has been shown that sialyltransferases are able to recognize different molecular species of the substrate, providing a mechanism aimed at maintaining the glycolipid ceramide pattern of a given tissue or cell situation (Kadowaki and Grant, 1995;Pitto et al, 1996).…”

Analysis of metabolites of bactrain camel milk in Alxa of China before and after fermentation with fermenting agent TR1 based on untargeted LC-MS/MS based metabolomics

“…N -acetyl- l -histidine had the lowest content among all down-regulated amino acids. Studies have shown that this substance can catalyze the synthesis of gangliosides [ 44 ], and high levels of certain specific gangliosides can lead to many genetic diseases. The significant decrease of N -acetyl- l -histidine in fermented camel milk indicated that fermented camel milk can effectively reduce the occurrence of many genetic diseases.…”