The influence of carbohydrate structure on the clearance of recombinant tissue-type plasminogen activator.
Modification of the carbohydrate structures of recombinant tissue-type plasminogen activator (rt-PA) can increase or decrease its rate of clearance in rabbits. When rt-PA was treated with sodium periodate to oxidize carbohydrate residues, the rate of clearance was decreased from 9.6 +/- 1.9 ml min-1 kg-1 to 3.5 +/- 0.6 ml min-1 kg-1 (mean +/- SD, n = 5). A similar change in the clearance of rt-PA was introduced by the use of endo-beta-N-acetyl-glucosaminidase H (Endo-H), which selectively removes high mannose asparagine-linked oligosaccharides; the clearance of Endo-H-treated rt-PA was 5.0 +/- 0.5 ml min-1 kg-1. A mutant of rt-PA was produced with an amino acid substitution at position 117 (Asn replaced with Gln) to remove a potential glycosylation site that normally contains a high mannose structure. The clearance of this material was also decreased, similar to the periodate and Endo-H-treated rt-PA. Conversely, when rt-PA was produced in the CHO 15B cell line, which can produce only high mannose oligosaccharide structures on glycoproteins, the clearance was increased by a factor of 1.8. These results demonstrate that the removal of rt-PA from the blood depends significantly upon the nature of its oligosaccharide structures.
Hotchkiss
A
A
Department of Pharmacological Sciences, Genentech, Inc., South San Francisco, CA.
Refino
C J
CJ
Leonard
C K
CK
O'Connor
J V
JV
Crowley
C
C
McCabe
J
J
Tate
K
K
Nakamura
G
G
Powers
D
D
Levinson
A
A
D000818:Animals; D002241:Carbohydrates; D002478:Cells, Cultured; D006224:Cricetinae; D005973:Glutamine / Q000032:analysis; D008358:Mannose / Q000032:analysis; D009154:Mutation; D009844:Oligosaccharides / Q000032:analysis; D010504:Periodic Acid / Q000494:pharmacology; D011817:Rabbits; D011994:Recombinant Proteins / Q000493:pharmacokinetics; D010959:Tissue Plasminogen Activator / Q000493:pharmacokinetics*
D002241:Carbohydrates; D009844:Oligosaccharides; D011994:Recombinant Proteins; D005973:Glutamine; D010504:Periodic Acid; D010959:Tissue Plasminogen Activator; D008358:Mannose