Matrix-assisted laser desorption ionization time-of-flight mass spectrometric analysis of glycosphingolipids including gangliosides

Long chain base compositions of gangliosides containing mainly stearic acid could be determined without any chemical modification by matrix-assisted l aser desorption ionization time-of-flight mass spectrometry with delayed io n extraction (DE MALDI-TOF MS). The analytical results for the long chain b ase compositions of various samples of G(M1) from the brain tissues of pati ents with different diseases at different ages confirmed that the proportio n of d20:1 (icosasphingosine) and d20 (icosa-sphinganine) of the total sphi ngosine bases increased quickly until adolescent or adult age and then rema ined constant slightly exceeding 50%; this value was evidently higher than the proportion of d20:1 and d20 of G(M1) in various adult mammalian brains. A long chain base composition of G(M1) from the brain tissue of a patient with infantile type of G(M1)-gangliosidosis at 4y2m was abnormal and so was in two sibling patients with Spielmeyer-Vogt type of juvenile amaurotic id iocy at 19y and 21y in spite of that in the latter there was no accumulatio n of G(M1) in the brain tissue. On the other hand, a patient with adult typ e of G(M1) gangliosidosis at 66y showed a local accumulation of G(M1) in th e putamen and caudate nucleus, but its long chain base composition was foun d to be normal. It was of interest that the white matter of Eker rat with hereditary renal carcinoma contained a large amount of plasmalocerebroside as compared with the amount of cerebroside and sphingomyelin. The individual molecular speci es of plasmalocerebroside were identified by DE MALDI-TOF MS.