The Institute of Physical and Chemical Research

Toshiro Hamamoto

Naoya Kojima

Nobuyuki Kurosawa

Shuichi Tsuji

Takashi Nakaoka

Young-Choon Lee

Yukiko Yoshida

Novel GalNAc&agr;2,6-sialyltransferases P-B1 and P-B3; GalNAc&agr;2,6-sialyltransferase genes encoding the above GalNAc&agr;2,6-sialyltransferases P-B1 and P-B3; and an extracellularly releasable protein catalyzing GalNAc&agr;2,6-sialic acid transfer which comprises a polypeptide portion as being an active domain of the GalNAc&agr;2,6-sialyltransferase P-B1 or P-B3 together with a signal peptide are provided. Also provided is a process for preparing a sialyltransferases which enables efficient recovery of a sialyltransferase expressed in a large quantity in microorganisms.

Sugar-chain synthetase and process for producing the same

The present invention provides a nucleotide sequence encoding Sia.alpha.2,3Gal.beta.1,4GlcNAc .alpha.2,8-sialyltransferase and an enzymatically active fragment thereof. The present invention also provides a nucleotide sequence encoding an extracellularly releasable protein capable of catalyzing Sia.alpha.2,3Gal.beta.1,4GlcNAc .alpha.2,8-sialyltransfer which comprises an enzymatically active fragment of the Sia.alpha.2,3Gal.beta.1,4GlcNAc .alpha.2,8-sialyltransferase together with a nucleotide sequence encoding at least one signal peptide. The present invention also provides recombinant vectors comprising nucleotide sequences encoding Sia.alpha.2,3Gal.beta.1,4GlcNAc .alpha.2,8-sialyltransferase. Processes for preparing extracellularly releasable polypeptide fragments of Sia.alpha.2,3Gal.beta.1,4GlcNAc .alpha.2,8-sialyltransferase are provided as well.

Sia.alpha. 2,3, Gal.beta. 1, 4Glc NAc.alpha. 2,8-sialyltransferase

The subject invention provides Sia.alpha.2,3 Gal.beta.1,4GlcNAc.alpha.2,8-sialyltransferase and an enzymatically active fragment thereof, and a nucleotide sequence encoding said sialyltransferase. The subject invention also provides an extracellularly releasable protein capable of catalyzing Sia.alpha.2,3Gal.beta.1,4GlcNAc.alpha.2,8-sialyltransfer which comprises the enzymatically active fragment of the Sia.alpha.2,3Gal.beta.1,4GlcNAc.alpha.2,8-sialyltransferase together with a signal peptide.

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Saitama, Japan

Toshiro Hamamoto