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PubMed1970

Incorporation of [14C] glucosamine and [14C] leucine into mouse kidney beta-glucuronidase induced by gonadotrophin.

Male BALB/C mice were injected intraperitoneally with 2.5 i.u. of gonadotrophin. After the injection, increase of beta-glucuronidase activity was first observed in the microsomal fraction. By 36h 45-50% of the total homogenate activity was found in the microsomal fraction compared with 20-25% in the control microsomal fraction. From 36 to 80h not only microsomal beta-glucuronidase but also lysosomal beta-glucuronidase increased progressively. After 69h stimulation with 2.5 i.u. of gonadotrophin, d-[1-(14)C]glucosamine or l-[U-(14)C]leucine was injected intraperitoneally. After a further 3h the kidneys were homogenized and five particulate fractions were prepared by differential centrifugation. The beta-glucuronidase in the microsomal and lysosomal fractions was released respectively by ultrasonication and by freezing and thawing treatment. The enzyme was purified by organic-solvent precipitation and by sucrose-density-gradient centrifugation. The results demonstrated the incorporation of these two labels into the mouse renal beta-glucuronidase. The microsomal beta-glucuronidase was much more radioactive than the lysosomal enzyme and approx. 80% of the newly synthesized enzyme appeared in microsomes and approx. 20% of that was found in lysosomes at this period. These results suggest that the mouse renal beta-glucuronidase is a glycoprotein and that the newly synthesized enzyme is transported from endoplasmic reticulum to lysosomes.

Animals↗

PubMed1970

N-iodoacetyl-D-glucosamine, an inhibitor of growth and glycoside uptake in Escherichia coli.

1. Synthesis of N-iodoacetyl-d-glucosamine and its N-iodo[1,2-(14)C(2)]acetyl form has been achieved from the tetra-O-acetyl amino sugar and iodoacetic acid in the presence of dicyclohexylcarbodi-imide followed by catalytic deacetylation. 2. N-Iodoacetylglucosamine (up to 0.1mm) linearly inhibits uptake (up to 1min) of methyl alpha-d-glucoside by Escherichia coli ML308 and K12. Uptake of methyl beta-d-thiogalactoside and glycerol is also inhibited. 3. Growth of the organism (strain ML308) on glucose, succinate and glycerol is strongly inhibited by the iodoacetyl compound. The inhibition is relieved by N-acetylglucosamine. 4. The inhibitor has multiple effects, some of which are considered to be intracellular. 5. A separate transport pathway exists for N-acetylglucosamine by means of which the iodoacetyl analogue may enter the cell.

Biological Transport, Active↗

PubMed1971

Studies on the control of hexosamine biosynthesis by glucosamine synthetase.

1. The nature of the feedback inhibition of hexosamine biosynthesis on rat liver glucosamine synthetase (l-glutamine-d-fructose 6-phosphate aminotransferase, EC 2.6.1.16) by UDP-N-acetylglucosamine was investigated in detail. 2. Further modifiers of physiological importance are described. Glucose 6-phosphate and AMP potentiated the UDP-N-acetylglucosamine inhibition, and UTP behaved as an activator. These three compounds only exerted their action when the feedback inhibitor was bound to the enzyme. 3. ATP also inhibited the enzyme. 4. The actions of these various effectors are discussed in kinetic terms. 5. An interpretation of these findings with reference to the regulation of hexosamine biosynthesis is presented.

Adenosine Triphosphate↗

PubMed1971

Binding of substrates and modifiers to glucosamine synthetase.

1. The binding of substrates and effectors to glucosamine synthetase (l-glutamine-d-fructose 6-phosphate aminotransferase, EC 2.6.1.16) was studied by using the ligand to alter the denaturation rate of the enzyme. The free enzyme bound fructose 6-phosphate, glucose 6-phosphate and UDP-N-acetylglucosamine, but not glutamine, AMP or UTP. Glucose 6-phosphate and AMP increased the binding of UDP-N-acetylglucosamine whereas UTP decreased the interaction between the enzyme and the feedback inhibitor. UDP-N-acetylglucosamine induced a glutamine-binding site on the enzyme. 2. Selective thermal or chemical denaturation revealed that the UDP-N-acetylglucosamine-binding site was not located at the catalytic site. The UTP site could not be distinguished from that for the nucleotide sugar. The AMP- and glucose 6-phosphate-binding sites were distinct from the catalytic and feedback-inhibitor-binding sites. 3. The specificity of the glutamine-binding site was investigated by using a series of potential analogues. 4. A model is proposed for the action of the effectors and the mechanism of the reaction discussed in kinetic and chemical terms.

Allosteric Regulation↗

PubMed1979

Crystal structures of hen egg-white lysozyme complexes with gadolinium(III) and gadolinium(III)-N-acetyl-D-glucosamine.

Analysis at 0.25 nm resolution of the crystal structures of lysozyme-Gd(III) and lysozyme-Gd(III)-N-acetyl-D-glucosamine (GlcNac), prepared by diffusion methods, show that there are two main binding positions for Gd(III), one of which is close to glutamic acid-35 and the other close to aspartic acid-52. The two sites are 0.36 nm part. There is no evidence for the weak binding of Gd(III) to any of the eight other carboxy groups of lysozyme. In the presence of Gd(III), the binding of GlcNac is similar to that observed for the binding of the beta-anomer in subsite C. There are numerous small conformational changes in the protein on binding (Gd(III) and the sugar, and these have been quantified to a first approximation by real-space refinement. These changes are similar in both structures, and involve, among other small movements, shifts of one of the disulphide bridges by up to 0.05 nm. The movement of residues 70--74 observed in the binary complex of lysozyme-GlcNac [Perkins, Johnson, Machin & Phillips (1978) Biochem. J. 173-617] is not observed in the ternary complex of lysozyme-Gd(III)-GlcNac. The nature of the lysozyme-Gd(III) complex is discussed in the light of evidence from other crystallographic studies and n.m.r. solution studies. Preliminary findings for a lysozyme-Gd(III) complex prepared by co-crystallization methods are reported.

Acetylglucosamine↗

PubMed2003

Effects of [3H]glucosamine concentration on [3H]chondroitin sulphate formation by cultured chondrocytes.

GlcN (glucosamine) is now promoted over the counter for implied treatment of osteoarthritis, ostensibly by stimulating biosynthesis of cartilage chondroitin sulphate. In order to evaluate whether exogenous GlcN has any stimulatory effect, we have incubated mouse chondrocytes with [(35)S]sulphate and various amounts of GlcN, to determine whether any increment in chondroitin [(35)S]sulphate formation occurs. Similarly we have used varying concentrations of [(3)H]GlcN to determine the dilution of incorporation into [(3)H]chondroitin sulphate due to provision of endogenous GlcN by metabolism from glucose at two different glucose concentrations. The incorporation of both (35)S and (3)H was essentially linear over a 5 h time period. We found no stimulation of chondroitin [(35)S]sulphate synthesis at lower concentrations of GlcN, and a significant reduction at higher concentrations. Even at concentrations of [(3)H]GlcN that were greater than could be achieved with standard doses of oral GlcN, there was significant dilution of exogenous GlcN. Furthermore, an artificial acceptor for glycosaminoglycan synthesis in cell culture, 4-methylumbelliferyl beta-D-xyloside, did not modify the provision of GlcN from endogenous sources, even though it stimulated chondroitin sulphate synthesis 4 -5-fold at each GlcN concentration. We conclude that the cells have excess capacity to form maximal amounts of GlcN from glucose so that exogenous GlcN does not stimulate chondroitin sulphate synthesis.

Animals↗

PubMed2005

Glucosamine induces cell-cycle arrest and hypertrophy of mesangial cells: implication of gangliosides.

Alterations in proliferation and hypertrophy of renal mesangial cells are typical features of diabetic nephropathy. The HP (hexosamine pathway) has been proposed as a biochemical hypothesis to explain microvascular alterations due to diabetic nephropathy; however, involvement of HP in the regulation of mesangial cell growth or hypertrophy has been poorly studied. Although gangliosides are known to regulate cell proliferation, their potential role in mesangial cell-growth perturbations has hardly been explored. In the present study, we investigated the effects of the HP activation, mimicked by GlcN (glucosamine) treatment, on mesangial cell growth and hypertrophy and the potential implication of gangliosides in these processes. Our results indicate that GlcN induced hypertrophy of mesangial cells, as measured by an increase in the protein/cell ratio, and it caused cell-cycle arrest by an increase in the expression of cyclin-dependent kinase inhibitor p21(Waf1/Cip1). Furthermore, GlcN treatment resulted in a massive increase in the levels of gangliosides G(M2) and G(M1). Treatment of cells with exogenous G(M2) and G(M1) reproduced the effects of 0.5 mM GlcN on p21(Waf1/Cip1) expression, cell-cycle arrest and hypertrophy, suggesting that gangliosides G(M2) and G(M1) are probably involved in mediating GlcN effects. These results document a new role of the HP in the regulation of mesangial cell growth and hypertrophy. They also suggest a potential new mechanism of action of the HP through modulation of ganglioside levels.

Animals↗

PubMed1984

Proteins of the kidney microvillar membrane. Effects of monensin, vinblastine, swainsonine and glucosamine on the processing and assembly of endopeptidase-24.11 and dipeptidyl peptidase IV in pig kidney slices.

The effects of various inhibitors were studied on the biogenesis of endopeptidase-24.11 (EC 3.4.24.11) and dipeptidyl peptidase IV (EC 3.4.14.5) in slices of renal cortex, from piglets of the Yucatan strain, maintained in organ culture. These microvillar peptidases were synthesized within membrane compartments and underwent glycosylation to yield high-mannose and complex forms [the preceding paper, Stewart & Kenny (1984) Biochem. J. 224, 549-558]. Monensin caused very gross ultrastructural changes in the proximal-tubular cells, resulting from distension of the Golgi sacs. It blocked the processing of the high-mannose to the complex glycosylated forms of the peptidases and prevented their assembly in the microvillar membrane. Swainsonine, an inhibitor of alpha-mannosidase II, generated new 'hybrid' forms of the proteins, intermediate in Mr between the high-mannose and the complex forms, but did not prevent assembly of the hybrid forms in microvilli. Vinblastine, an agent that affects microtubules, delayed, but did not abolish, either the processing or the transport to microvilli. Glucosamine interfered with the initial glycosylation reactions and generated heterogeneous sets of partially glycosylated polypeptides of lower Mr than the high-mannose forms. These results are discussed in relation to the site and mechanism of glycosylation and the involvement of the Golgi complex and microtubules in the biogenesis of these membrane peptidases.

Alkaloids↗

PubMed1991

Sequence analysis of heparan sulphate indicates defined location of N-sulphated glucosamine and iduronate 2-sulphate residues proximal to the protein-linkage region.

A strategy that we originally used to identify an N-acetylated domain adjacent to the protein-linkage sequence of heparan sulphate proteoglycan (HSPG) [Lyon, Steward, Hampson & Gallagher (1987) Biochem. J. 242, 493-498] has been adapted for analysis of the location of GlcNSO3-HexA and GlcNSO3(+/- 6S)-IdoA(2S) units most proximal to the core protein. [3H]Glucosamine-labelled HSPG from human skin fibroblasts was depolymerized by using HNO2 or heparinase under conditions that allowed cleavage of all susceptible linkages. The degraded PG was coupled to Sepharose beads through the protein component, enabling specific recovery of protein-linked resistant oligosaccharides. These were released by treatment with alkaline borohydride and analysed by gel filtration and gradient PAGE. This strategy allowed investigation of the sequence of sugar residues along the chain relative to a common reference point (i.e. the reducing end of the chain). HNO2 scission confirmed the presence of a well-defined N-acetylated sequence predominantly 9-12 disaccharide units in length proximal to the core protein. Heparinase scission produced two classes of oligosaccharides (Mr approx. 7000 and 15,000) with the general formula: IdoA(2S)-GlcNSO3-[HexA-GlcNR]n-HexA-GlcNSO3-[Hex A-GlcNAc]9 12-GlcA-Gal-Gal-Xyl in which the average value for n is 1-2 for the 7000-Mr species and approx. 22 for the 15,000-Mr species. The latter oligosaccharides extend to about one-third of the total length of the HS chains (Mr approx. 45,000). HNO2 scission of these oligosaccharides enabled hypothetical models for their sequence to be proposed. The general arrangement of N-sulphated and N-acetylated disaccharides between the proximal GlcNSO3 and terminal IdoA(2S) residues of the 15,000-Mr fragment was similar to that in the original polysaccharide, suggesting the possibility of a tandemly repeating pattern in the sequence of HS.

Carbohydrate Sequence↗

PubMed2000

Glucosamine sulfate modulates dysregulated activities of human osteoarthritic chondrocytes in vitro.

OBJECTIVE: The efficacy of glucosamine sulfate (GS) in the symptomatic treatment of patients with osteoarthritis (OA) is suggested to be mediated by still unknown effects on the altered OA cartilage. DESIGN: Using human OA chondrocytes in culture, the effects of GS on protein synthesis, caseinase, collagenase, phospholipase A2 (PLA2) and protein kinase C (PKC) activities as well as production of nitric oxide and cyclic AMP were studied in both cells and culture medium. RESULTS: GS significantly reduced PLA2 activity, and more modestly collagenase activity, in the OA chondrocytes in a dose-dependent manner. By contrast, PLA2 and collagenase activity of the culture medium was not modified. No effects on caseinase activity was seen. GS significantly and dose-dependently increased protein synthesis. GS did not modify nitric oxide and cAMP production but significantly increased PKC production. CONCLUSION: GS modified cultured OA chondrocyte metabolism by acting on PKC, cellular PLA2, protein synthesis and possibly collagenase activation. Extrapolation of the effect to the in-vivo situation remains hypothetical but they might represent some possible mechanisms of action of the drug in human.

Caseins↗

PubMed2001

Effects of an orally administered mixture of chondroitin sulfate, glucosamine hydrochloride and manganese ascorbate on synovial fluid chondroitin sulfate 3B3 and 7D4 epitope in a canine cruciate ligament transection model of osteoarthritis.

OBJECTIVE: To evaluate effects of an orally administered mixture of chondroitin sulfate, glucosamine hydrochloride and manganese ascorbate (CS-G-M) on articular cartilage metabolism in dogs with cranial cruciate ligament (CCL) deficient and reconstructed knees, as reflected by concentrations of synovial fluid 3B3, 7D4 and total sulfated glycosaminoglycan (GAG). METHODS: Sixteen adult dogs that underwent unilateral CCL transection were randomized into four groups. Thereafter, group I (N=3) had a sham CCL reconstruction, group II (N=3) had CS-G-M and sham CCL reconstruction, group III (N=5) had CCL reconstruction, and group IV (N=5) had CS-G-M and CCL reconstruction. Synovial fluid collected at 0, 1, 3 and 5 months was examined by ELISA for 3B3 and 7D4 epitope, and by DMMB assay for total GAG. RESULTS: Synovial fluid from CCL transected knees of CS-G-M treated dogs contained significantly elevated concentrations of 3B3 (P=0.029), 7D4 (P=0.036) and 7D4/GAG (P=0.007) in comparison to controls, in a cross-sectional analysis at 3 months. Furthermore, 7D4 and 7D4/GAG concentrations remained significantly elevated (P=0.012) in CCL transected knees of CS-G-M treated dogs over the 5 month period. However, when epitope concentrations were expressed as a ratio of CCL-transected to contralateral non-operated knee, treatment effect of CS-G-M was no longer significant. Reconstruction of the CCL had no significant effect on synovial fluid epitope. CONCLUSIONS: Administration of CS-G-M was associated with altered concentrations of 3B3 and 7D4 epitope in synovial fluid, suggesting that these compounds may act to modulate articular cartilage matrix metabolism in vivo.

Administration, Oral↗

PubMed2003

Glucosamine and chondroitin sulfate are effective in the management of osteoarthritis.

The use of glucosamine and chondroitin sulfate for the symptomatic treatment of osteoarthritis has been a subject of controversy for several reasons. First, the medical community in general took offense at the title of Theodosakis' book, The Arthritis Cure. Second, the medical community is becoming divided into "traditional" and "alternative" camps with deep skepticism between them. Third, the whole nutraceutical industry is essentially unregulated, with manufacturers making outrageous claims on products that have never been tested at all, are often of poor quality, and occasionally lacking in any active ingredient. However, for the nutriceuticals evaluated here, there is abundant in vitro, in vivo, animal clinical, and human clinical evidence of both their efficacy and safety. They deserve a prominent place in the armamentarium of nonsurgical treatment of osteoarthritis.

Animals↗

PubMed1970

Immunoglobulin synthesis and secretion. V. Incorporation of leucine and glucosamine into immunoglobulin on free and bound polyribosomes.

Mouse myeloma cells pulse-labeled in vitro with (3)H-leucine or (3)H-glucosamine were fractionated on sucrose gradients, and membrane-bound and free polyribosomes were separated. Nascent polypeptides released from polyribosomes were precipitated with antiserum specific for mouse immunoglobulin. The results indicate that immunoglobulin is synthesized preferentially by bound polyribosomes.

Animals↗

PubMed1981

Comparison of [3H]glucosamine-labeled glycoproteins from human renal cancer and normal kidney epithelial cell cultures by two-dimensional polyacrylamide gel electrophoresis.

Two-dimensional polyacrylamide gel electrophoresis has been used to compare the Nonidet P-40 soluble, [3H]glucosamine-labeled glycoproteins of human kidney cancer cell lines and short-term cultures of normal kidney epithelia. Two pairs of autologous combinations of tumor and normal cells and also six other cancer lines and four normal cultures were examined. Because autologous cells could be compared, possible differences due to allogeneic variations could be eliminated. The electrophoretic patterns given by tumor and normal cells were extremely similar. Nevertheless, more than 10 differences could be recognized when randomly selected combinations of cancer and normal cells were examined in detail. Of these differences, however, only one was consistently found in all possible combinations of cancer and normal cells. Cancer cells had three prominent components of molecular weight 27,500 and pIs of 5.7, 5.3, and 4.9, respectively. Normal cells have a fainter and different constellation of spots in this region, with the more acid component (pI 4.9) being absent (or barely detectable). The pattern of fetal kidney cells resembled that given by normal adult kidney.

Cell Line↗

PubMed1995

Endothelial heparan sulfate proteoglycans that bind to L-selectin have glucosamine residues with unsubstituted amino groups.

We earlier reported calcium-dependent, heparin-like L-selectin ligands in cultured bovine endothelial cells (Norgard-Sumnicht, K. E., Varki, N. M., and Varki, A. (1993) Science 261,480-483). Here we show that these are heparan sulfate proteoglycans (HSPGs) associated either with the cultured cells or secreted into the medium and extracellular matrix. Activation of the endothelial cells with bacterial lipopolysaccharide (LPS) does not markedly alter the amount or distribution of this material. A major portion of the glycosaminoglycan (GAG) chains released from these HSPGs by alkaline beta-elimination rebinds to L-selectin in the presence of calcium, indicating that these saccharides alone can mediate the high affinity recognition. Heparin lyase digestions indicate that these GAG chains are enriched in heparan sulfate, not heparin sequences. Current understanding of the biosynthesis of heparan sulfate chains indicates that all glucosamine amino groups must be either N-acetylated or N-sulfated. However, nitrous acid deamination at pH 4.0 suggests the presence of some unsubstituted amino groups in these L-selectin-binding GAG chains from endothelial cell HSPGs. This is confirmed by chemical N-reacetylation and by reactivity with sulfo-N-hydroxysuccinimide-biotin. These unsubstituted amino groups are also found on HSPGs from human umbilical vein endothelial cells, but are not detected in those from Chinese hamster ovary cells. In both bovine and human endothelial cells, these novel groups are enriched for in the HS-GAG chains which bind to L-selectin. Despite this, studies with N-reacetylation and nitrous acid deamination do not show conclusive evidence for the direct involvement of the unsubstituted amino groups in L-selectin binding. This may be because the chemical reactions used to modify the amino groups do not go to completion. Alternatively, the unsubstituted amino groups may only be indirectly involved in generating binding, by dictating the biosynthesis of another critical group. Regardless, these studies shown that HSPGs from cultured endothelial cells which can bind to L-selectin are enriched with unsubstituted amino groups on their GAG chains. The possible biochemical mechanisms for generation of these novel groups are discussed.

Acetylation↗

PubMed1996

Acylation of glucosaminyl phosphatidylinositol revisited. Palmitoyl-CoA dependent palmitoylation of the inositol residue of a synthetic dioctanoyl glucosaminyl phosphatidylinositol by hamster membranes permits efficient mannosylation of the glucosamine residue.

Two critical steps in the assembly of yeast and mammalian glycosylphosphatidylinositol (GPI) anchor precursors are palmitoylation of the inositol residue and mannosylation of the glucosamine residue of the glucosaminyl phosphatidylinositol (GlcNalpha-PI) intermediate. Palmitoylation has been reported to be acyl-CoA dependent in yeast membranes (Costello, L. C., and Orlean, P. (1992) J. Biol. Chem. 267, 8599-8603) but strictly acyl-CoA independent in rodent membranes (Stevens, V. L., and Zhang, H. (1994) J. Biol. Chem. 269, 31397-31403), and thus poorly conserved. In addition, it was suggested that acylation must precede mannosylation in both yeast (Costello, L. C., and Orlean, P. (1992) J. Biol. Chem. 276, 8599-8603) and rodent (Urakaze, M., Kamitani, T., DeGasperi, R., Sugiyama, E., Chang, H.-M., Warren, C. D., and Yeh, E. T. H. (1992) J. Biol. Chem. 267, 6459-6462) cells because GlcNalpha-acyl-PI accumulates in vivo when mannosylation is blocked. However, GlcNalpha-acyl-PI accumulation would also be expected if mannosylation and acylation were independent of each other. These issues were addressed by the use of a synthetic dioctanoyl GlcNalpha-PI analogue (GlcNalpha-PI(C8)) as an in vitro substrate for GPI-synthesizing enzymes in Chinese hamster ovary cell membranes. GlcNalpha-PI(C8) was acylated in an manner requiring acyl-CoA. Thus, the process involving acyl-CoA reported for yeast has been conserved in mammals. Furthermore, both GlcNalpha-PI(C8) and GlcNalpha-acyl-PI(C8) could be mannosylated in vitro, but mannosylation of the latter was significantly more efficient. This provides direct support for the earlier suggestion that acylation precedes mannosylation in rodents cells. A similar result was also observed with the Saccharomyces cerevisiae mannosyltransferase. In contrast, it has been reported that mannosylation of endogenous GlcNalpha-PI by Trypansoma brucei membranes occurs without prior acylation. The same result was obtained with GlcNalpha-PI(C8), confirming that the mannosyltransferase of trypanosomes is divergent from those in yeasts and rodents.

Acyl Coenzyme A↗

PubMed2000

Cloning and characterization of the murine glucosamine-6-phosphate acetyltransferase EMeg32. Differential expression and intracellular membrane association.

N-Linked glycosylation is a post-translational modification occurring in many eukaryotic secreted and surface-bound proteins and has impact on diverse physiological and pathological processes. Similarly important is the generation of glycosylphosphatidylinositol linkers, which anchor membrane proteins to the cell. Both protein modifications depend on the central nucleotide sugar UDP-N-acetylglucosamine (UDP-GlcNAc). The enzymatic reactions leading to generation of nucleotide sugars are established, yet most of the respective genes still await cloning. We describe the characterization of such a gene, EMeg32, which we identified based on its differential expression in murine hematopoietic precursor cells. We further demonstrate regulated expression during embryogenesis. EMeg32 codes for a 184-amino acid protein exhibiting glucosamine-6-phosphate acetyltransferase activity. It thereby holds a key position in the pathway toward de novo UDP-GlcNAc synthesis. Surprisingly, the protein associates with the cytoplasmic side of various intracellular membranes, accumulates prior to mitosis, and copurifies with the cdc48 homolog p97/valosin-containing protein.

Acetyltransferases↗

PubMed2002

Isolation of a glucosamine-specific kinase, a unique enzyme of Vibrio cholerae.

We showed previously that chitin catabolism by the marine bacterium Vibrio furnissii involves at least three signal transduction systems and many genes, several of which were molecularly cloned, and the corresponding proteins were characterized. The predicted amino acid sequences of these proteins showed a high degree of identity to the corresponding proteins from Vibrio cholerae, whose complete genomic sequence has recently been determined. We have therefore initiated studies with V. cholerae. We report here a novel ATP-dependent glucosamine kinase of V. cholerae encoded by a gene designated gspK. The protein, GspK (31.6 kDa), was purified to apparent homogeneity from recombinant Escherichia coli. The product of the reaction was shown to be GlcN-6-P by matrix-assisted laser desorption/ionization-time of flight (MALDI mass spectrometry) and NMR. The K(m) values for GlcN, ATP, and MgCl(2) were 0.45, 2.4, and 2.2 mm, respectively, and the V(max) values were in the range 180-200 nmol/microg/min (approximately 6 nmol/pmol/min). Kinase activity was not observed with any other sugar, including: galactosamine, mannosamine, Glc, GlcNAc, GalNAc, mannose, 2-deoxyglucose, and oligosaccharides of chitosan. The enzyme is also ATP-specific. The kinase can be used to specifically determine micro quantities of GlcN in acid hydrolysates of glycoconjugates. The physiological function of this enzyme remains to be determined.

Bacterial Proteins↗