EC Number   |
Substrates |
Organism |
Products |
Reversibility |
|---|
   3.2.1.B43 | corneal keratan sulfate + H2O |
compared with cornea keratan sulfate, keratan sulfates from human nucleus pulposus and shark cartilage are attacked at lower rates with a resultant production of oligosaccharides of relatively large size. The point of enzyme attack is limited to the endo-beta-D-galactoside bonds in which nonsulfated D-galactose residues participate. The bond susceptible to hydrolysis is associated with beta-D-Gal-(1->4)-2-acetamido-2-deoxy-6-O-sulfo-n-glucose in keratan sulfate. The major oligosaccharide products in the digest are terminated by galactose and 2-acetamido-2-deoxy-6-O-sulfoglucose at the reducing and nonreducing end, respectively |
Pseudomonas sp. IFO-13309 |
? |
- |
? |
| 3.2.1.B43 | keratan sulfate + H2O |
hydrolyzes keratan sulfate between the 4GlcNAcbeta1-3Gal1 structure, digests shark cartilage keratan sulfate to disaccharides and tetrasaccharides and bovine cornea keratan sulfate to hexasaccharides, prefers highly sulfated keratan sulfate |
Niallia circulans |
? |
- |
? |
| 3.2.1.B43 | keratan sulfate + H2O |
the enzyme hydrolyzes the beta1-3-glucosaminidic linkages to galactose in keratan sulfate, when the 6-O-position of GlcNAc is sulfated. It degrades not only B type 2-type 2 keratan sulfate but also type 1-type 2 keratan sulfate, significantly |
Bacillus sp. Ks36 |
? |
- |
? |
| 3.2.1.B43 | more |
no substrates are: desulfated keratan sulfate, hyaluronic acid, chondroitin sulfate C, heparan sulfate, heparin |
Niallia circulans |
? |
- |
? |
| 3.2.1.B43 | more |
specificity of the transglycosylation. The oxazoline derivative of 6-O-sulfonato-N-acetyllactosamine is processively oligomerized to the corresponding hexamer or longer. This result strongly implies that the enzyme has the large positively numbered subsites. In contrast, the transglycosylation of the su-LacNAc oxazoline donor with the 6-O-sulfonato-Lewis X (su-LeX) acceptor solely gave the su-LacNAc-su-LeX pentasaccharide. In addition, both the oxazoline derivatives of su-LeX and 6,6'-di-O-sulfonato-LacNAc are exclusively oligomerized to the corresponding dimers respectively. These results strongly suggest that the steric hindrance exists around the (+3)(+4) subsites in keratanase II. Furthermore, KSase II-catalyzed reaction of the excess su-LeX oxazoline with the su-LacNAc gives the su-LeX-su-LacNAc pentasaccharide as the sole transglycosylation product, also implying the steric hindrance at the catalytic center hampering processive shift of this pentasaccharide. Thus, KSase II has the sterically crowded structures at the catalytic center and around the (+3)(+4) subsites, which are all expected to be tunnel-like |
Niallia circulans |
? |
- |
? |
| 3.2.1.B43 | more |
the enzyme does not catalyze the hydrolysis of phenyl beta-D-galactoside. beta-D-Gal-(1->3)-2-acetamido-2-deoxy-beta-D-Glc-(1->3)-beta-D-Gal-(1->4)-D-Glc is completely refractory to the action of this enzyme |
Pseudomonas sp. IFO-13309 |
? |
- |
? |
| 3.2.1.B43 | more |
the enzyme efficiently catalyzes the transglycosylation reaction of the sulfated Lewis X (Gal-beta-(1->4)-[Fuc-alpha-(1->3)]-GlcNAc(6-OSO3-)) (su-Lex) soxazoline derivative, thereby giving the su-Lex dimer as the main product in good yields. Exclusive formation of the beta-(1->3) glycosidic bond |
Niallia circulans |
? |
- |
? |
| 3.2.1.B43 | more |
the enzyme efficiently catalyzes the transglycosylation reaction of the sulfated Lewis X (Gal-beta-(1->4)-[Fuc-alpha-(1->3)]-GlcNAc(6-OSO3-)) (su-Lex) soxazoline derivative, thereby giving the su-Lex dimer as the main product in good yields. Exclusive formation of the beta-(1->3) glycosidic bond |
Bacillus sp. Ks36 |
? |
- |
? |
| 3.2.1.B43 | more |
transglycosylation to form beta-(1->3)-glycosidic bond through a substrate-assisted mechanism. N-Acetyllactosamine oxazoline derivatives with sulfate groups at the C-6 are effectively oligomerized by the enzyme under weak alkaline conditions, to give alternating 6-sulfated keratan sulfate oligomers in good yields. The enzyme also recognized N-acetyllactosamine oxazoline derivatives with sulfate groups at both the C-6 and the C-6', which provides fully 6-sulfated KS oligomers in good yields under similar conditions. Nonsulfated LacNAc oxazoline is difficult to oligomerize enzymatically. The catalysis mechanism of KSase II involves a sugar oxazolinium ion that requires the 6-sulfate group in the GlcNAc residue not only in hydrolysis of keratan sulfate chains, but also in oligomerization of oxazoline monomers |
Bacillus sp. Ks36 |
? |
- |
? |
| 3.2.1.B43 | more |
specificity of the transglycosylation. The oxazoline derivative of 6-O-sulfonato-N-acetyllactosamine is processively oligomerized to the corresponding hexamer or longer. This result strongly implies that the enzyme has the large positively numbered subsites. In contrast, the transglycosylation of the su-LacNAc oxazoline donor with the 6-O-sulfonato-Lewis X (su-LeX) acceptor solely gave the su-LacNAc-su-LeX pentasaccharide. In addition, both the oxazoline derivatives of su-LeX and 6,6'-di-O-sulfonato-LacNAc are exclusively oligomerized to the corresponding dimers respectively. These results strongly suggest that the steric hindrance exists around the (+3)(+4) subsites in keratanase II. Furthermore, KSase II-catalyzed reaction of the excess su-LeX oxazoline with the su-LacNAc gives the su-LeX-su-LacNAc pentasaccharide as the sole transglycosylation product, also implying the steric hindrance at the catalytic center hampering processive shift of this pentasaccharide. Thus, KSase II has the sterically crowded structures at the catalytic center and around the (+3)(+4) subsites, which are all expected to be tunnel-like |
Niallia circulans KsT202 |
? |
- |
? |
