Saposin-C from bovine spleen; complete amino acid sequence and relation between the structure and its biological activity.
Saposin-C, a small acidic glycoprotein that can activate glucosylceramide-beta-glucosidase, has been isolated from bovine spleen. The complete amino acid sequence of bovine saposin-C was determined by Edman degradation of the purified protein and its fragmented peptides. It contains 80 amino acids, one carbohydrate chain attached to a single asparagine residue and six cysteine residues in oxidized form. The sequence of bovine saposin-C is 76 and 65% identical with the sequences of saposin-C from human spleen and guinea pig liver, respectively. Hydropathy profiles of the sequence of saposin-C from three species were similar despite the significant residue substitutions. Bovine saposin-C had a stronger effect in stimulating bovine beta-glucosidase compared to human saposin-C. However, the effect of human saposin-C in stimulating human enzyme was stronger than that of bovine saposin-C. The region around residue 35, which is next to the extremely hydrophilic region, seems to be important to produce an interaction with the enzyme.
Sano
A
A
Department of Neuropsychiatry, Ehime University School of Medicine, Japan.
Mizuno
T
T
Kondoh
K
K
Hineno
T
T
Ueno
S
S
Kakimoto
Y
Y
Morita
N
N
D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D004789:Enzyme Activation; D006023:Glycoproteins; D008969:Molecular Sequence Data; D011506:Proteins / Q000302:isolation & purification*; D049231:Saposins; D016415:Sequence Alignment; D013154:Spleen / Q000737:chemistry*; D013329:Structure-Activity Relationship; D001617:beta-Glucosidase / Q000378:metabolism
D006023:Glycoproteins; D011506:Proteins; D049231:Saposins; D001617:beta-Glucosidase