Densimetric determination of carbohydrate content in glycoproteins.
Carbohydrates play important roles in activity, stability and pharmacokinetics of glycoproteins and the degree of glycosylation varies with proteins. In this communication, a simple method of determining the carbohydrate content was developed, which consists of measuring the density increments of a glycoprotein and its non-glycosylated counterpart, and then dividing the difference between the two values by the density increment of carbohydrates. The density increment was relatively constant for various sugars except for sialic acid, and hence assumed to be 0.39. Thus, we obtained carbohydrate contents of 38, 28, 8 and 7% for Chinese hamster ovary cell-expressed erythropoietin (EPO), stem cell factor (SCF), granulocyte-colony-stimulating factor (G-CSF), and platelet-derived growth factor (PDGF), respectively. These values are in close agreement with those determined by other methods.
Kolvenbach
C G
CG
Amgen Inc., Amgen Center, Thousand Oaks, California 91320.
Langley
K E
KE
Strickland
T W
TW
Kenney
W C
WC
Arakawa
T
T
D000818:Animals; D016466:CHO Cells; D002241:Carbohydrates / Q000032:analysis*; D006224:Cricetinae; D003412:Cricetulus; D003720:Densitometry / Q000379:methods; D004921:Erythropoietin / Q000737:chemistry; D005260:Female; D006023:Glycoproteins / Q000737:chemistry*; D016179:Granulocyte Colony-Stimulating Factor / Q000737:chemistry; D016298:Hematopoietic Cell Growth Factors / Q000737:chemistry; D010982:Platelet-Derived Growth Factor / Q000737:chemistry
D002241:Carbohydrates; D006023:Glycoproteins; D016298:Hematopoietic Cell Growth Factors; D010982:Platelet-Derived Growth Factor; D004921:Erythropoietin; D016179:Granulocyte Colony-Stimulating Factor