Studies on galactosyl ceramide and lactosyl ceramide β-galactosidase

✍ Scribed by David A. Wenger

• Book ID: 103040676
• Publisher: Elsevier Science
• Year: 1974
• Tongue: English
• Weight: 897 KB
• Volume: 13
• Category: Article
• ISSN: 0009-3084
• DOI: 10.1016/0009-3084(74)90007-3

✦ Synopsis

Galactosyl ceramide and lactosyl ceramide ~3-galactosidase activity was measured in extracts of previously frozen human brain. Using the assay methods described here, both galactosyl ceramide and lactosyl ceramide gave Michaelis constants of about 20 ~M. Evidence from these studies indicates that at least a major portion of human brain lactosyl ceramide t3-galactosidase activity is identical to galactosyl ceramide/3-galactosida~e activity. The evidence includes the following: co-purification by all methods tried, identical heat denaturation pattern under various conditions, same response to chemical inhibitors or stimulators, competitive inhibition with either substrate by the other, and severe deficiency of both galactosyl ceramide and lactosyl ceramide (~-galactosidase activity in all tissues tested from patients with Krabbe's disease. Liver, brain, fibroblast, leukocyte and spleen extracts from patients with GM1 gangliosidosis had normal ability to degrade both galactosyl ceramide and lactosyl ceramide.