n acetylglucosaminyltransferases


Summary: Enzymes that catalyze the transfer of N-acetylglucosamine from a nucleoside diphosphate N-acetylglucosamine to an acceptor molecule which is frequently another carbohydrate. EC 2.4.1.-.

Top Publications

  1. Song Y, Aglipay J, Bernstein J, Goswami S, Stanley P. The bisecting GlcNAc on N-glycans inhibits growth factor signaling and retards mammary tumor progression. Cancer Res. 2010;70:3361-71 pubmed publisher
    ..Thus, the addition of the bisecting GlcNAc to complex N-glycans of mammary tumor cell glycoprotein receptors is a cell autonomous mechanism serving to retard tumor progression by reducing growth factor signaling. ..
  2. Butkinaree C, Park K, Hart G. O-linked beta-N-acetylglucosamine (O-GlcNAc): Extensive crosstalk with phosphorylation to regulate signaling and transcription in response to nutrients and stress. Biochim Biophys Acta. 2010;1800:96-106 pubmed publisher
    ..Abnormal crosstalk between GlcNAcylation and phosphorylation underlies dysregulation in diabetes, including glucose toxicity, and defective GlcNAcylation is involved in neurodegenerative disease and cancer and most recently in AIDS. ..
  3. Glick R, Khaldi L, Ptaszynski K, Steiner G. Dysplasia epiphysealis hemimelica (Trevor disease): a rare developmental disorder of bone mimicking osteochondroma of long bones. Hum Pathol. 2007;38:1265-72 pubmed
    ..The histologic differences in combination with the distinct clinical and radiographic features should enable a pathologist to differentiate these entities...
  4. Whelan S, Lane M, Hart G. Regulation of the O-linked beta-N-acetylglucosamine transferase by insulin signaling. J Biol Chem. 2008;283:21411-7 pubmed publisher
    ..We conclude that insulin stimulates the tyrosine phosphorylation and activity of OGT. ..
  5. Li X, Zhang P, Yang Y, Xiong Y, Qi Y, Hu H. Differentiation and developmental origin of cerebellar granule neuron ectopia in protein O-mannose UDP-N-acetylglucosaminyl transferase 1 knockout mice. Neuroscience. 2008;152:391-406 pubmed publisher
    ..Moreover, migration into the IGL is not required for granule cell acquisition of certain differentiated characteristics...
  6. Ishimura H, Takahashi T, Nakagawa H, Nishimura S, Arai Y, Horikawa Y, et al. N-acetylglucosaminyltransferase V and beta1-6 branching N-linked oligosaccharides are associated with good prognosis of patients with bladder cancer. Clin Cancer Res. 2006;12:2506-11 pubmed
    ..GnT-V and its resultant beta1-6 branching N-linked oligosaccharides are closely related to low malignant potential and good prognosis of the patients with bladder cancer. ..
  7. Ide Y, Miyoshi E, Nakagawa T, Gu J, Tanemura M, Nishida T, et al. Aberrant expression of N-acetylglucosaminyltransferase-IVa and IVb (GnT-IVa and b) in pancreatic cancer. Biochem Biophys Res Commun. 2006;341:478-82 pubmed
    ..These results suggest that the down-regulation of GnT-IVa in pancreatic cancer cells is due to an epigenetic abnormality in the gene. ..
  8. Jager M, Westhoff B, Portier S, Leube B, Hardt K, Royer Pokora B, et al. Clinical outcome and genotype in patients with hereditary multiple exostoses. J Orthop Res. 2007;25:1541-51 pubmed
    ..c) 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:1541-1551, 2007...
  9. Godfrey C, Clement E, Mein R, Brockington M, Smith J, Talim B, et al. Refining genotype phenotype correlations in muscular dystrophies with defective glycosylation of dystroglycan. Brain. 2007;130:2725-35 pubmed
    ..Mutations in these five glycosyltransferase genes were detected in 34% of patients indicating that, after the exclusion of FKRP, the majority of patients with a dystroglycanopathy harbour mutations in novel genes. ..

More Information


  1. Seko A, Yamashita K. Activation of beta1,3-N-acetylglucosaminyltransferase-2 (beta3Gn-T2) by beta3Gn-T8. Possible involvement of beta3Gn-T8 in increasing poly-N-acetyllactosamine chains in differentiated HL-60 cells. J Biol Chem. 2008;283:33094-100 pubmed publisher
    ..These results raise a possibility that up-regulation of beta3Gn-T8 in differentiated HL-60 cells increases poly-N-acetyllactosamine chains by activating intrinsic beta3Gn-T2. ..
  2. Dehennaut V, Hanoulle X, Bodart J, Vilain J, Michalski J, Landrieu I, et al. Microinjection of recombinant O-GlcNAc transferase potentiates Xenopus oocytes M-phase entry. Biochem Biophys Res Commun. 2008;369:539-46 pubmed publisher
    ..Microinjection of anti-OGT antibodies leads to a delay of the GVBD kinetics. Our results hence demonstrate that OGT is a key molecule for the timely progression of the cell cycle. ..
  3. Cheung W, Hart G. AMP-activated protein kinase and p38 MAPK activate O-GlcNAcylation of neuronal proteins during glucose deprivation. J Biol Chem. 2008;283:13009-20 pubmed publisher
  4. Copeland R, Bullen J, Hart G. Cross-talk between GlcNAcylation and phosphorylation: roles in insulin resistance and glucose toxicity. Am J Physiol Endocrinol Metab. 2008;295:E17-28 pubmed publisher
  5. Slawson C, Lakshmanan T, Knapp S, Hart G. A mitotic GlcNAcylation/phosphorylation signaling complex alters the posttranslational state of the cytoskeletal protein vimentin. Mol Biol Cell. 2008;19:4130-40 pubmed publisher
    ..Together, these data demonstrate that the O-GlcNAc cycling enzymes associate with kinases and phosphatases at M phase to regulate the posttranslational status of vimentin. ..
  6. Cheung P, Dennis J. Mgat5 and Pten interact to regulate cell growth and polarity. Glycobiology. 2007;17:767-73 pubmed
    ..Taken together, our results reveal that Mgat5 and Pten interact in an opposing manner to regulate cellular sensitivities to extracelluar growth cues. ..
  7. Yoshida Moriguchi T, Yu L, Stalnaker S, Davis S, Kunz S, Madson M, et al. O-mannosyl phosphorylation of alpha-dystroglycan is required for laminin binding. Science. 2010;327:88-92 pubmed publisher
    ..These findings expand our understanding of the mechanisms that underlie congenital muscular dystrophy. ..
  8. Lazarus B, Love D, Hanover J. Recombinant O-GlcNAc transferase isoforms: identification of O-GlcNAcase, yes tyrosine kinase, and tau as isoform-specific substrates. Glycobiology. 2006;16:415-21 pubmed
    ..The identification of a tyrosine kinase and O-GlcNAcase as OGT targets suggests the potential for OGT participation in numerous signal transduction cascades. ..
  9. Bovee J. Multiple osteochondromas. Orphanet J Rare Dis. 2008;3:3 pubmed publisher
    ..For secondary peripheral chondrosarcoma, en-bloc resection of the lesion and its pseudocapsule with tumour-free margins, preferably in a bone tumour referral centre, should be performed...
  10. Guo H, Randolph M, Pierce M. Inhibition of a specific N-glycosylation activity results in attenuation of breast carcinoma cell invasiveness-related phenotypes: inhibition of epidermal growth factor-induced dephosphorylation of focal adhesion kinase. J Biol Chem. 2007;282:22150-62 pubmed
    ..These effects suppressed EGF-mediated downstream signaling and invasiveness-related phenotypes and suggest GnT-V as a potential therapeutic target. ..
  11. Hameetman L, Szuhai K, Yavas A, Knijnenburg J, van Duin M, van Dekken H, et al. The role of EXT1 in nonhereditary osteochondroma: identification of homozygous deletions. J Natl Cancer Inst. 2007;99:396-406 pubmed
    ..We examined whether EXT1 might act as a classical tumor suppressor gene for nonhereditary osteochondromas...
  12. Dehennaut V, Lefebvre T, Sellier C, Leroy Y, Gross B, Walker S, et al. O-linked N-acetylglucosaminyltransferase inhibition prevents G2/M transition in Xenopus laevis oocytes. J Biol Chem. 2007;282:12527-36 pubmed
    ..The present work underlines a crucial role for O-GlcNAc in G(2)/M transition and strongly suggests that its function is required for cell cycle regulation. ..
  13. Signori E, Massi E, Matera M, Poscente M, Gravina C, Falcone G, et al. A combined analytical approach reveals novel EXT1/2 gene mutations in a large cohort of Italian multiple osteochondromas patients. Genes Chromosomes Cancer. 2007;46:470-7 pubmed
    ..More important, we were able to characterize all those patients who were negative at the first PCR-based method screening. ..
  14. Lagana A, Goetz J, Cheung P, Raz A, Dennis J, Nabi I. Galectin binding to Mgat5-modified N-glycans regulates fibronectin matrix remodeling in tumor cells. Mol Cell Biol. 2006;26:3181-93 pubmed
  15. Huang M, Chen H, Huang H, Huang J, Liang J, Shen T, et al. C2GnT-M is downregulated in colorectal cancer and its re-expression causes growth inhibition of colon cancer cells. Oncogene. 2006;25:3267-76 pubmed
    ..Tumor growth in vivo was also significantly suppressed by C2GnT-M in the xenografts of nude mice. These results demonstrate that C2GnT-M is frequently downregulated in colorectal cancer and suppresses colon cancer cell growth. ..
  16. Thorens B. A toggle for type 2 diabetes?. N Engl J Med. 2006;354:1636-8 pubmed
  17. Wang Z, Pandey A, Hart G. Dynamic interplay between O-linked N-acetylglucosaminylation and glycogen synthase kinase-3-dependent phosphorylation. Mol Cell Proteomics. 2007;6:1365-79 pubmed
    ..Taken together, these data indicated the complex interplay between phosphorylation and O-GlcNAcylation that occurs within signaling networks. ..
  18. Liu J, Ball S, Yang Y, Mei P, Zhang L, Shi H, et al. A genetic model for muscle-eye-brain disease in mice lacking protein O-mannose 1,2-N-acetylglucosaminyltransferase (POMGnT1). Mech Dev. 2006;123:228-40 pubmed
    ..The present study provides the first genetic animal model to further dissect the roles of POMGnT1 in MEB disease. ..
  19. Hartweck L, Genger R, Grey W, Olszewski N. SECRET AGENT and SPINDLY have overlapping roles in the development of Arabidopsis thaliana L. Heyn. J Exp Bot. 2006;57:865-75 pubmed
    ..These results are consistent with SEC function overlapping with SPY for leaf production and reproductive development. ..
  20. Togayachi A, Kozono Y, Ishida H, Abe S, Suzuki N, Tsunoda Y, et al. Polylactosamine on glycoproteins influences basal levels of lymphocyte and macrophage activation. Proc Natl Acad Sci U S A. 2007;104:15829-34 pubmed
    ..These results indicate that polylactosamine on N-glycans is a putative immune regulatory factor presumably suppressing excessive responses during immune reactions. ..
  21. Aaron M, Charbon G, Lam H, Schwarz H, Vollmer W, Jacobs Wagner C. The tubulin homologue FtsZ contributes to cell elongation by guiding cell wall precursor synthesis in Caulobacter crescentus. Mol Microbiol. 2007;64:938-52 pubmed
    ..Evidence suggests that bacteria use both a FtsZ-independent and a FtsZ-dependent mode of peptidoglycan synthesis to elongate, the importance of each mode depending on the timing of FtsZ assembly during elongation. ..
  22. Hameetman L, David G, Yavas A, White S, Taminiau A, Cleton Jansen A, et al. Decreased EXT expression and intracellular accumulation of heparan sulphate proteoglycan in osteochondromas and peripheral chondrosarcomas. J Pathol. 2007;211:399-409 pubmed
    ..We hypothesize that loss of EXT expression disrupts the function of the EXT1/2 complex in HSPG biosynthesis, resulting in the intracellular accumulation of HSPG core proteins that we found in these tumours...
  23. Nadanaka S, Kitagawa H. Heparan sulphate biosynthesis and disease. J Biochem. 2008;144:7-14 pubmed publisher
    ..This review suggests that HS biosynthetic enzymes would be potential candidates for drug targets in various diseases...
  24. Saint Jore Dupas C, Nebenführ A, Boulaflous A, Follet Gueye M, Plasson C, Hawes C, et al. Plant N-glycan processing enzymes employ different targeting mechanisms for their spatial arrangement along the secretory pathway. Plant Cell. 2006;18:3182-200 pubmed
    ..We conclude that the localization of N-glycan processing enzymes corresponds to an assembly line in the early secretory pathway and depends on both TMD length and signals in the cytoplasmic tail. ..
  25. Ohtsubo K, Takamatsu S, Minowa M, Yoshida A, Takeuchi M, Marth J. Dietary and genetic control of glucose transporter 2 glycosylation promotes insulin secretion in suppressing diabetes. Cell. 2005;123:1307-21 pubmed
    ..We infer that beta cell glucose-transporter glycosylation mediates a link between diet and insulin production that typically suppresses the pathogenesis of type 2 diabetes. ..
  26. Xiong H, Kobayashi K, Tachikawa M, Manya H, Takeda S, Chiyonobu T, et al. Molecular interaction between fukutin and POMGnT1 in the glycosylation pathway of alpha-dystroglycan. Biochem Biophys Res Commun. 2006;350:935-41 pubmed
    ..From these findings, we propose that fukutin forms a complex with POMGnT1 and may modulate its enzymatic activity. ..
  27. Gordon R, Sivarajah P, Satkunarajah M, Ma D, Tarling C, Vizitiu D, et al. X-ray crystal structures of rabbit N-acetylglucosaminyltransferase I (GnT I) in complex with donor substrate analogues. J Mol Biol. 2006;360:67-79 pubmed
  28. Alvarez C, De Vera M, Heslip T, Casey B. Evaluation of the anatomic burden of patients with hereditary multiple exostoses. Clin Orthop Relat Res. 2007;462:73-9 pubmed
    ..EXT1 patients were shorter. All limb segments tended to be shorter for EXT1 subjects. EXT1 subjects showed more anatomic burden with respect to lesion quality and height...
  29. Hajduch J, Nam G, Kim E, Frohlich R, Hanover J, Kirk K. A convenient synthesis of the C-1-phosphonate analogue of UDP-GlcNAc and its evaluation as an inhibitor of O-linked GlcNAc transferase (OGT). Carbohydr Res. 2008;343:189-95 pubmed
    ..Deoxygenation, coupling of the resulting phosphonic acid with UMP and deprotection gave the target molecule as a di-sodium salt. This analogue had no detectable activity as an inhibitor of (OGT). ..
  30. Martinez Fleites C, Macauley M, He Y, Shen D, Vocadlo D, Davies G. Structure of an O-GlcNAc transferase homolog provides insight into intracellular glycosylation. Nat Struct Mol Biol. 2008;15:764-5 pubmed publisher
    ..UDP-GlcNAc:polypeptidyl transferase (OGT) catalyzes O-GlcNAc addition. The structure of an intact OGT homolog and kinetic analysis of human OGT variants reveal a contiguous superhelical groove that directs substrates to the active site. ..
  31. Yang X, Ongusaha P, Miles P, Havstad J, Zhang F, So W, et al. Phosphoinositide signalling links O-GlcNAc transferase to insulin resistance. Nature. 2008;451:964-9 pubmed publisher
    ..These findings identify a molecular mechanism by which nutritional cues regulate insulin signalling through O-GlcNAc, and underscore the contribution of this modification to the aetiology of insulin resistance and type 2 diabetes. ..
  32. Zhao Y, Sato Y, Isaji T, Fukuda T, Matsumoto A, Miyoshi E, et al. Branched N-glycans regulate the biological functions of integrins and cadherins. FEBS J. 2008;275:1939-48 pubmed publisher
    ..Collectively, N-glycans on adhesion molecules, especially those on E-cadherin and integrins, play key roles in cell-cell and cell-extracellular matrix interactions, thereby affecting cancer metastasis. ..
  33. Cheung W, Sakabe K, Housley M, Dias W, Hart G. O-linked beta-N-acetylglucosaminyltransferase substrate specificity is regulated by myosin phosphatase targeting and other interacting proteins. J Biol Chem. 2008;283:33935-41 pubmed publisher
    ..Furthermore depletion of MYPT1 in Neuro-2a neuroblastoma cells alters GlcNAcylation of several proteins under basal conditions, suggesting that MYPT1 regulates OGT substrate specificity in vivo. ..
  34. Clement E, Godfrey C, Tan J, Brockington M, Torelli S, Feng L, et al. Mild POMGnT1 mutations underlie a novel limb-girdle muscular dystrophy variant. Arch Neurol. 2008;65:137-41 pubmed publisher
    ..We propose that this condition be known as LGMD2M. The enzyme assay used to diagnose muscle-eye-brain disease may not detect subtle abnormalities of POMGnT1 function, and additional kinetic studies must be carried out in such cases. ..
  35. Bovée J, Hameetman L, Kroon H, Aigner T, Hogendoorn P. EXT-related pathways are not involved in the pathogenesis of dysplasia epiphysealis hemimelica and metachondromatosis. J Pathol. 2006;209:411-9 pubmed
    ..Downstream targets of EXT, which are downregulated in osteochondroma, are expressed in DEH and MC, suggesting that EXT signalling is not disturbed...
  36. Manya H, Bouchet C, Yanagisawa A, Vuillaumier Barrot S, Quijano Roy S, Suzuki Y, et al. Protein O-mannosyltransferase activities in lymphoblasts from patients with alpha-dystroglycanopathies. Neuromuscul Disord. 2008;18:45-51 pubmed
    ..In conclusion, the lymphoblast-based enzymatic assay is a sensitive and useful method (i) to select patients harbouring POMGNT1, POMT1 or POMT2 mutations; (ii) to assess the pathogenicity of new or already described mutations. ..
  37. Hu H, Yang Y, Eade A, Xiong Y, Qi Y. Breaches of the pial basement membrane and disappearance of the glia limitans during development underlie the cortical lamination defect in the mouse model of muscle-eye-brain disease. J Comp Neurol. 2007;501:168-83 pubmed
  38. Lonie L, Porter D, Fraser M, Cole T, Wise C, Yates L, et al. Determination of the mutation spectrum of the EXT1/EXT2 genes in British Caucasian patients with multiple osteochondromas, and exclusion of six candidate genes in EXT negative cases. Hum Mutat. 2006;27:1160 pubmed
    ..This technique was found to be sensitive with a detection rate of 100% regarding heterozygote detection for EXT mutation scanning. Furthermore, this technique has a very high throughput and is very cost-effective...
  39. Stanley P, Sundaram S, Tang J, Shi S. Molecular analysis of three gain-of-function CHO mutants that add the bisecting GlcNAc to N-glycans. Glycobiology. 2005;15:43-53 pubmed publisher
    ..LEC10B is therefore the cell line of choice for producing recombinant glycoproteins carrying bisected N-glycans and for investigating biological functions of the bisecting GlcNAc...
  40. Norton W, Ledin J, Grandel H, Neumann C. HSPG synthesis by zebrafish Ext2 and Extl3 is required for Fgf10 signalling during limb development. Development. 2005;132:4963-73 pubmed
    ..This reveals an unexpected specificity of HSPGs in regulating distinct vertebrate Fgfs. ..
  41. van Reeuwijk J, Brunner H, van Bokhoven H. Glyc-O-genetics of Walker-Warburg syndrome. Clin Genet. 2005;67:281-9 pubmed
    ..Perhaps, the missing genes underlying the remainder of the unexplained WWS patients have also to be sought in the pathways involved in O-linked protein glycosylation. ..
  42. Lefebvre T, Guinez C, Dehennaut V, Beseme Dekeyser O, Morelle W, Michalski J. Does O-GlcNAc play a role in neurodegenerative diseases?. Expert Rev Proteomics. 2005;2:265-75 pubmed
    ..The data presented in this review strongly suggest that O-GlcNAc could play an active role in neurodegenerative diseases. ..
  43. Tomiie M, Isaka S, Miyoshi E, Taniguchi N, Kimura T, Ogita K, et al. Elevated expression of N-acetylglucosaminyltransferase V in first trimester human placenta. Biochem Biophys Res Commun. 2005;330:999-1004 pubmed
    ..These results suggest that GnT-V would contribute to placentation in the early phase of pregnancy, possibly regulating the process of invasion of trophoblast cells. ..
  44. Iwai T, Kudo T, Kawamoto R, Kubota T, Togayachi A, Hiruma T, et al. Core 3 synthase is down-regulated in colon carcinoma and profoundly suppresses the metastatic potential of carcinoma cells. Proc Natl Acad Sci U S A. 2005;102:4572-7 pubmed
    ..v. injection of the transfectants into nude mice was significantly suppressed. These findings indicated that the core structures of O-glycans are profoundly involved in the metastatic capacity of cancer cells. ..
  45. Koziel L, Kunath M, Kelly O, Vortkamp A. Ext1-dependent heparan sulfate regulates the range of Ihh signaling during endochondral ossification. Dev Cell. 2004;6:801-13 pubmed
    ..Finally, we propose that the development of exostoses in the human Hereditary Multiple Exostoses syndrome can be attributed to activation of Ihh signaling...
  46. Hanover J, Forsythe M, Hennessey P, Brodigan T, Love D, Ashwell G, et al. A Caenorhabditis elegans model of insulin resistance: altered macronutrient storage and dauer formation in an OGT-1 knockout. Proc Natl Acad Sci U S A. 2005;102:11266-71 pubmed
    ..Our findings demonstrate that OGT modulates macronutrient storage and dauer formation in C. elegans, providing a unique genetic model for examining the role of O-GlcNAc in cellular signaling and insulin resistance. ..
  47. Hilton M, Gutierrez L, Martinez D, Wells D. EXT1 regulates chondrocyte proliferation and differentiation during endochondral bone development. Bone. 2005;36:379-86 pubmed
    ..Our results indicate that defects in EXT1 and the resulting reduction in HS lead to enhanced Indian Hedgehog diffusion causing an increase in chondrocyte proliferation and delayed hypertrophic differentiation. ..
  48. Patnaik S, Stanley P. Mouse large can modify complex N- and mucin O-glycans on alpha-dystroglycan to induce laminin binding. J Biol Chem. 2005;280:20851-9 pubmed
    ..In addition, the data suggest that human LARGE may restore functional alpha-DG to muscle cells from patients with defective synthesis of O-mannose glycans via the modification of N-glycans and/or mucin O-glycans on alpha-DG. ..
  49. Grewal P, McLaughlan J, Moore C, Browning C, Hewitt J. Characterization of the LARGE family of putative glycosyltransferases associated with dystroglycanopathies. Glycobiology. 2005;15:912-23 pubmed
    ..Thus, there may be functional redundancy between LARGE1 and LARGE2. Consistent with this idea, we show that alpha-DG is still fully glycosylated in kidney (a tissue that expresses a high level of LARGE2 mRNA) of Large(myd) mutant mice. ..
  50. Helm J, Hu Y, Chen L, Gross B, Walker S. Identification of active-site inhibitors of MurG using a generalizable, high-throughput glycosyltransferase screen. J Am Chem Soc. 2003;125:11168-9 pubmed
    ..We discuss the implications of this result and the utility of the screen for identifying inhibitors of other glycosyltransferases. ..
  51. Dosaka Akita H, Miyoshi E, Suzuki O, Itoh T, Katoh H, Taniguchi N. Expression of N-acetylglucosaminyltransferase v is associated with prognosis and histology in non-small cell lung cancers. Clin Cancer Res. 2004;10:1773-9 pubmed
    ..GnT-V expression is associated with histology in NSCLCs. Low GnT-V expression is associated with shorter survival and poor prognosis in pStage I overall NSCLCs and non-squamous cell carcinomas. ..
  52. Lemos M, Kotanko P, Christie P, Harding B, Javor T, Smith C, et al. A novel EXT1 splice site mutation in a kindred with hereditary multiple exostosis and osteoporosis. J Clin Endocrinol Metab. 2005;90:5386-92 pubmed
    ..A novel heterozygous acceptor splice site mutation of EXT1 results in HME that is associated with a low peak bone mass, indicating a possible additional role for EXT1 in bone biology and in regulating BMD. ..
  53. Smith M, Smith B, Lawrence M, Snapp K. Functional analysis of the combined role of the O-linked branching enzyme core 2 beta1-6-N-glucosaminyltransferase and dimerization of P-selectin glycoprotein ligand-1 in rolling on P-selectin. J Biol Chem. 2004;279:21984-91 pubmed
    ..Both C2GlcNAcT-I glycosylation and PSGL-1 dimerization increased the rate of tethering to P-selectin under flow, whereas C2GlcNAcT-I levels primarily influenced tether bond strength. ..