Dataset Information

Comparison of biological activities of human antithrombins with high-mannose or complex-type nonfucosylated N-linked oligosaccharides.

ABSTRACT: The structure of the N-linked oligosaccharides attached to antithrombin (AT) has been shown to affect its anticoagulant activity and pharmacokinetics. Human AT has biantennary complex-type oligosaccharides with the unique feature of lacking a core fucose, which affects its biological activities by changing its heparin-binding affinity. In human plasma, AT circulates as a mixture of the ?-form bearing four oligosaccharides and the ?-form lacking an oligosaccharide at Asn135. However, it remains unclear how the immature high-mannose-type oligosaccharides produced by mammalian cells affect biological activities of AT. Here, we succeeded in directly comparing the activities between the high-mannose and complex types. Interestingly, although there were no substantial differences in thrombin inhibitory activity, the high-mannose type showed higher heparin-binding affinity. The anticoagulant activities were increased by heparin and correlated with the heparin-binding affinity, resulting in the strongest anticoagulant activity being displayed in the ?-form with the high-mannose type. In pharmacokinetic profiling, the high-mannose type showed a much shorter plasma half-life than the complex type. The ?-form was found to have a prolonged plasma half-life compared with the ?-form for the high-mannose type; conversely, the ?-form showed a longer half-life than the ?-form for the complex-type. The present study highlights that AT physiological activities are strictly controlled not only by a core fucose at the reducing end but also by the high-mannose-type structures at the nonreducing end. The ?-form with the immature high-mannose type appears to function as a more potent anticoagulant than the AT typically found in human plasma, once it emerges in the blood.

SUBMITTER: Yamada T

PROVIDER: S-EPMC4813732 | biostudies-literature | 2016 May

REPOSITORIES: biostudies-literature

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Comparison of biological activities of human antithrombins with high-mannose or complex-type nonfucosylated N-linked oligosaccharides.

Yamada Tsuyoshi T Kanda Yutaka Y Takayama Makoto M Hashimoto Akitoshi A Sugihara Tsutomu T Satoh-Kubota Ai A Suzuki-Takanami Eri E Yano Keiichi K Iida Shigeru S Satoh Mitsuo M

Glycobiology 20160107 5

The structure of the N-linked oligosaccharides attached to antithrombin (AT) has been shown to affect its anticoagulant activity and pharmacokinetics. Human AT has biantennary complex-type oligosaccharides with the unique feature of lacking a core fucose, which affects its biological activities by changing its heparin-binding affinity. In human plasma, AT circulates as a mixture of the α-form bearing four oligosaccharides and the β-form lacking an oligosaccharide at Asn135. However, it remains u ...[more]

PMID: 26747427

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Project description:The insulin receptor is synthesized as a 190,000-Mr single-chain precursor that contains exclusively asparagine-N-linked high-mannose-type carbohydrate chains. In this study we have characterized the structure of the pro-receptor oligosaccharides. IM-9 lymphocytes were pulse-chase-labelled with [3H]mannose, and the insulin pro-receptor was isolated by immunoprecipitation and SDS/polyacrylamide-gel electrophoresis. The pro-receptor oligosaccharides were removed from the protein backbone with endoglycosidase H and analysed by h.p.l.c. Immediately after a [3H]mannose pulse the largest oligosaccharide found in the pro-receptor was Glc1Man9GlcNAc2; this structure represented only a small fraction (3%) of the total. The predominant oligosaccharides present in the pro-receptor were Man9GlcNAc2 (25%) and Man8GlcNAc2 (48%). Smaller oligosaccharides were also detected: Man7GlcNAc2 (18%), Man6GlcNAc2 (3%) and Man5GlcNAc2 (3%). The relative distribution of the different oligosaccharides did not change at 1, 2 or 3 h after the pulse with the exception of the rapid disappearance of the Glc1Man9GlcNAc2 component. The mature alpha- and beta-subunits of the insulin receptor are known to contain both high-mannose-type and complex-type oligosaccharides. We have also examined here the structure of the high-mannose chains of these subunits. The predominant species in the alpha-subunit was Man8GlcNAc2 whereas in the beta-subunit it was Man7GlcNAc2. These results demonstrate that most (approx. 75%) oligosaccharides of the insulin pro-receptor are chains of the type Man8GlcNAc2 or Man9GlcNAc2. Thus, assuming that a Glc3Man9GlcNAc2 species is transferred co-translationally, carbohydrate processing of the pro-receptor appears to be very rapid and limited to the removal of the three glucose residues and one mannose residue. Further mannose removal does not occur until the pro-receptor has been proteolytically cleaved. In addition, the degree of mannose trimming appears to be different in the alpha- and beta-subunits.

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Dataset Information

Comparison of biological activities of human antithrombins with high-mannose or complex-type nonfucosylated N-linked oligosaccharides.

Publications

Comparison of biological activities of human antithrombins with high-mannose or complex-type nonfucosylated N-linked oligosaccharides.

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