J T Brosnan

Summary

Affiliation: Memorial University of Newfoundland
Country: Canada

Publications

  1. doi request reprint Glutamate: a truly functional amino acid
    John T Brosnan
    Department of Biochemistry, Memorial University of Newfoundland, St John s, NL, A1B 3X9, Canada
    Amino Acids 45:413-8. 2013
  2. ncbi request reprint The sulfur-containing amino acids: an overview
    John T Brosnan
    Department of Biochemistry, Memorial University of Newfoundland, St John s, NL, Canada A1B 3X9
    J Nutr 136:1636S-1640S. 2006
  3. ncbi request reprint Branched-chain amino acids: enzyme and substrate regulation
    John T Brosnan
    Department of Biochemistry, Memorial University of Newfoundland, St John s, NL, Canada
    J Nutr 136:207S-11S. 2006
  4. ncbi request reprint Creatine: endogenous metabolite, dietary, and therapeutic supplement
    John T Brosnan
    Department of Biochemistry, Memorial University of Newfoundland, St John s, Newfoundland, Canada
    Annu Rev Nutr 27:241-61. 2007
  5. ncbi request reprint Amino acids and the regulation of methyl balance in humans
    John T Brosnan
    Department of Biochemistry, Memorial University of Newfoundland, St John s, Newfoundland, Canada
    Curr Opin Clin Nutr Metab Care 10:52-7. 2007
  6. doi request reprint Creatine synthesis is a major metabolic process in neonatal piglets and has important implications for amino acid metabolism and methyl balance
    John T Brosnan
    Department of Biochemistry, Memorial University of Newfoundland, St John s, Canada A1B 3X9
    J Nutr 139:1292-7. 2009
  7. doi request reprint Creatine metabolism and the urea cycle
    John T Brosnan
    Department of Biochemistry, Memorial University of Newfoundland, St John s, NL, Canada
    Mol Genet Metab 100:S49-52. 2010
  8. ncbi request reprint Methylation demand: a key determinant of homocysteine metabolism
    John T Brosnan
    Department of Biochemistry, Memorial University of Newfoundland, St John s, Canada
    Acta Biochim Pol 51:405-13. 2004
  9. ncbi request reprint Interorgan amino acid transport and its regulation
    John T Brosnan
    Department of Biochemistry, Memorial University of Newfoundland, St John s, NF Canada A1B 3X9
    J Nutr 133:2068S-2072S. 2003
  10. doi request reprint The metabolic burden of creatine synthesis
    John T Brosnan
    Department of Biochemistry, Memorial University of Newfoundland, St John s, NL, Canada
    Amino Acids 40:1325-31. 2011

Collaborators

Detail Information

Publications47

  1. doi request reprint Glutamate: a truly functional amino acid
    John T Brosnan
    Department of Biochemistry, Memorial University of Newfoundland, St John s, NL, A1B 3X9, Canada
    Amino Acids 45:413-8. 2013
    ..The finding of glutamate receptors throughout the gastrointestinal tract has opened up a new vista in glutamate function. Glutamate is truly a functional amino acid. ..
  2. ncbi request reprint The sulfur-containing amino acids: an overview
    John T Brosnan
    Department of Biochemistry, Memorial University of Newfoundland, St John s, NL, Canada A1B 3X9
    J Nutr 136:1636S-1640S. 2006
    ..Cysteine may be converted to such important products as glutathione and taurine. Taurine is present in many tissues at higher concentrations than any of the other amino acids. It is an essential nutrient for cats...
  3. ncbi request reprint Branched-chain amino acids: enzyme and substrate regulation
    John T Brosnan
    Department of Biochemistry, Memorial University of Newfoundland, St John s, NL, Canada
    J Nutr 136:207S-11S. 2006
    ..Cytosolic and mitochondrial isoenzymes of BCAT have been identified. They are thought to play an important role in brain neurotransmitter metabolism...
  4. ncbi request reprint Creatine: endogenous metabolite, dietary, and therapeutic supplement
    John T Brosnan
    Department of Biochemistry, Memorial University of Newfoundland, St John s, Newfoundland, Canada
    Annu Rev Nutr 27:241-61. 2007
    ..It is evident that creatine plays a critical, though underappreciated, role in brain function...
  5. ncbi request reprint Amino acids and the regulation of methyl balance in humans
    John T Brosnan
    Department of Biochemistry, Memorial University of Newfoundland, St John s, Newfoundland, Canada
    Curr Opin Clin Nutr Metab Care 10:52-7. 2007
    ..Amino acids are intimately involved in these processes...
  6. doi request reprint Creatine synthesis is a major metabolic process in neonatal piglets and has important implications for amino acid metabolism and methyl balance
    John T Brosnan
    Department of Biochemistry, Memorial University of Newfoundland, St John s, Canada A1B 3X9
    J Nutr 139:1292-7. 2009
    ..Creatine synthesis is a quantitatively major metabolic process in piglets...
  7. doi request reprint Creatine metabolism and the urea cycle
    John T Brosnan
    Department of Biochemistry, Memorial University of Newfoundland, St John s, NL, Canada
    Mol Genet Metab 100:S49-52. 2010
    ..It is clear that patients with urea cycle disorders also have altered creatine metabolism. Whether this contributes in a significant way to their neurological symptoms remains an open question...
  8. ncbi request reprint Methylation demand: a key determinant of homocysteine metabolism
    John T Brosnan
    Department of Biochemistry, Memorial University of Newfoundland, St John s, Canada
    Acta Biochim Pol 51:405-13. 2004
    ..There are also important genetic influences on homocysteine metabolism...
  9. ncbi request reprint Interorgan amino acid transport and its regulation
    John T Brosnan
    Department of Biochemistry, Memorial University of Newfoundland, St John s, NF Canada A1B 3X9
    J Nutr 133:2068S-2072S. 2003
    ..There is no single means of regulating amino acid fluxes; rather, such varied mechanisms as substrate supply, enzyme activity, transporter activity and competitive inhibition of transport are all found...
  10. doi request reprint The metabolic burden of creatine synthesis
    John T Brosnan
    Department of Biochemistry, Memorial University of Newfoundland, St John s, NL, Canada
    Amino Acids 40:1325-31. 2011
    ..Creatine synthesis is, therefore, a quantitatively major pathway in amino acid metabolism and imposes an appreciable burden on the metabolism of methionine and of arginine...
  11. pmc Formate can differentiate between hyperhomocysteinemia due to impaired remethylation and impaired transsulfuration
    Simon G Lamarre
    Dept of Biochemistry, Memorial University of Newfoundland, St John s, NL, Canada
    Am J Physiol Endocrinol Metab 302:E61-7. 2012
    ....
  12. ncbi request reprint Amino acids, then and now--a reflection on Sir Hans Krebs' contribution to nitrogen metabolism
    J T Brosnan
    Department of Biochemistry, Memorial University of Newfoundland, St John s, Canada
    IUBMB Life 52:265-70. 2001
    ..This paper addresses three of Krebs' early contributions-urea synthesis, glutamine metabolism, and D-amino acid oxidase-and relates them to our modern understanding of amino acid metabolism...
  13. ncbi request reprint Methylation demand and homocysteine metabolism: effects of dietary provision of creatine and guanidinoacetate
    L M Stead
    Department of Biochemistry, Memorial University of Newfoundland, St John s, Newfoundland, Canada A1B 3X9
    Am J Physiol Endocrinol Metab 281:E1095-100. 2001
    ..Creatine, however, was without effect. These results suggest that homocysteine metabolism is sensitive to methylation demand imposed by physiological substrates...
  14. ncbi request reprint Hyperglucagonemia in rats results in decreased plasma homocysteine and increased flux through the transsulfuration pathway in liver
    R L Jacobs
    Department of Biochemistry, Memorial University of Newfoundland, St. John's, Newfoundland A1B 3X9, Canada
    J Biol Chem 276:43740-7. 2001
    ..These results indicate that glucagon can regulate plasma homocysteine through its effects on the hepatic transsulfuration pathway...
  15. ncbi request reprint Effects of streptozotocin-induced diabetes and of insulin treatment on homocysteine metabolism in the rat
    R L Jacobs
    Department of Biochemistry, Memorial University of Newfoundland, St John s, Canada
    Diabetes 47:1967-70. 1998
    ..These results suggest that insulin is involved in the regulation of plasma homocysteine concentrations by affecting the hepatic transsulfuration pathway, which is involved in the catabolism of homocysteine...
  16. ncbi request reprint Threonine metabolism in isolated rat hepatocytes
    J D House
    Department of Biochemistry, Memorial University of Newfoundland, St. John's, Newfoundland, A1B 3X9, Canada
    Am J Physiol Endocrinol Metab 281:E1300-7. 2001
    ..In summary, the majority of threonine oxidation occurs through the threonine dehydratase pathway in rat hepatocytes, and threonine oxidation is increased by glucagon, which also increases threonine's transport...
  17. ncbi request reprint Hepatic glutaminase--a special role in urea synthesis?
    John T Brosnan
    Department of Biochemistry, Memorial University of Newfoundland, St John s, Newfoundland A1B 3X9, Canada
    Nutrition 18:455-7. 2002
    ..To investigate the relationship between hepatic glutaminase and the urea cycle with particular reference to the possibility of the existence of a metabolic channel between glutaminase and carbamylphosphate synthetase I (CPS-I)...
  18. ncbi request reprint Creatine synthesis: production of guanidinoacetate by the rat and human kidney in vivo
    Erica E Edison
    Dept of Biochemistry, Memorial Univ of Newfoundland, St John s, NL, Canada, A1B 3X9
    Am J Physiol Renal Physiol 293:F1799-804. 2007
    ..9 microM. In humans, [GAA] was 2.4 microM in arterial plasma, with a renal A-V difference of -1.1 microM. These studies show, for the first time, that GAA is produced by both rat and human kidneys in vivo...
  19. ncbi request reprint Orotic acid excretion and arginine metabolism
    Margaret E Brosnan
    Department of Biochemistry, Memorial University of Newfoundland, St John s, NL, Canada A1B 3X9
    J Nutr 137:1656S-1661S. 2007
    ....
  20. ncbi request reprint Is it time to reevaluate methyl balance in humans?
    Lori M Stead
    Department of Biochemistry, Memorial University of Newfoundland, St John s, Canada
    Am J Clin Nutr 83:5-10. 2006
    ....
  21. ncbi request reprint The Fourth Workshop on the Assessment of Adequate intake of Dietary Amino Acids: general discussion of sessions 1 and 2
    John T Brosnan
    Department of Biochemistry, Memorial University of Newfoundland, St John s, NL, Canada
    J Nutr 135:1576S-9S. 2005
  22. doi request reprint Systemic activation of glutamate dehydrogenase increases renal ammoniagenesis: implications for the hyperinsulinism/hyperammonemia syndrome
    Jason R Treberg
    Department of Biochemistry, Memorial University of Newfoundland, St John s, Newfoundland, Canada
    Am J Physiol Endocrinol Metab 298:E1219-25. 2010
    ..These results are discussed in relation to the organ source of the ammonia in the HI/HA syndrome as well as the role of GDH in regulating renal ammoniagenesis...
  23. ncbi request reprint Methylation demand and homocysteine metabolism
    Lori M Stead
    Department of Biochemistry, Memorial University of Newfoundland, St John s, NL, Canada A1B 3X9
    Adv Enzyme Regul 44:321-33. 2004
  24. ncbi request reprint Renal arginine metabolism
    Margaret E Brosnan
    Department of Biochemistry, Memorial University of Newfoundland, St John s, NL, Canada, A1B 3X9
    J Nutr 134:2791S-2795S; discussion 2796S-2797S. 2004
    ..Arginine is transported out of the proximal tubular cells at the basolateral membrane by another heteromeric transporter, which also transports lysine and ornithine. Defects in this transporter cause lysinuric protein intolerance...
  25. ncbi request reprint A window into cellular metabolism: hepatic metabolism of (15)N-labelled substrates
    John T Brosnan
    Department of Biochemistry, Memorial University of Newfoundland, St John s, NF, Canada A1B 3X9
    Metab Eng 6:6-11. 2004
    ..Our studies indicate that a metabolic channel does not exist between glutaminase and carbamoylphosphate synthetase 1...
  26. doi request reprint The simultaneous determination of NAD(H) and NADP(H) utilization by glutamate dehydrogenase
    Jason R Treberg
    Department of Biochemistry, Memorial University of Newfoundland, St John s, NL, Canada
    Mol Cell Biochem 344:253-9. 2010
    ..These results illustrate that simple assumptions of cofactor preference by mammalian GDH are incomplete without an appreciation of allosteric effects when both cofactors are simultaneously present...
  27. ncbi request reprint Homocysteine metabolism in diabetes
    E P Wijekoon
    Department of Biochemistry, Memorial University of Newfoundland, St John s, NL, Canada A1B 3X9
    Biochem Soc Trans 35:1175-9. 2007
    ....
  28. pmc Creatine synthesis: hepatic metabolism of guanidinoacetate and creatine in the rat in vitro and in vivo
    Robin P da Silva
    Dept of Biochemistry, Memorial Univ of Newfoundland, St John s, NL, Canada A1B3X9
    Am J Physiol Endocrinol Metab 296:E256-61. 2009
    ..They also illustrate the interplay between the dietary provision of creatine and its de novo synthesis and point to the crucial role of renal AGAT expression in regulating creatine synthesis in the rat...
  29. ncbi request reprint Amino acid metabolism in the Zucker diabetic fatty rat: effects of insulin resistance and of type 2 diabetes
    Enoka P Wijekoon
    Department of Biochemistry, Memorial University of Newfoundland, St John s, Canada
    Can J Physiol Pharmacol 82:506-14. 2004
    ..These changes in amino acid concentrations are similar to changes seen in type 1 diabetes. It is evident that insulin resistance alone is capable of bringing about many of the changes in amino acid metabolism observed in type 2 diabetes...
  30. pmc Homocysteine metabolism in ZDF (type 2) diabetic rats
    Enoka P Wijekoon
    Department of Biochemistry, Memorial University of Newfoundland, St John s, Newfoundland, Canada
    Diabetes 54:3245-51. 2005
    ..These results emphasize the importance of betaine metabolism in determining plasma Hcy levels in type 2 diabetes...
  31. ncbi request reprint Alanine metabolism in the perfused rat liver. Studies with (15)N
    J T Brosnan
    Department of Biochemistry, Memorial University of Newfoundland, St. John's, Newfoundland A1B 3X9, Canada
    J Biol Chem 276:31876-82. 2001
    ..Under these circumstances, the liver must summon internal pools of protein in order to accommodate the ammonia burden...
  32. ncbi request reprint Application of 15N to the study of hepatic nitrogen metabolism
    John T Brosnan
    Department of Biochemistry, Memorial University of Newfoundland, St John s, NF A1B 3X9, Canada
    Adv Enzyme Regul 42:305-15. 2002
  33. doi request reprint Lack of phosphatidylethanolamine N-methyltransferase alters plasma VLDL phospholipids and attenuates atherosclerosis in mice
    Yang Zhao
    Department of Biochemistry, University of Alberta, Edmonton, Canada
    Arterioscler Thromb Vasc Biol 29:1349-55. 2009
    ..We, therefore, tested the hypothesis that lack of phosphatidylethanolamine N-methyltransferase (PEMT), a hepatic enzyme catalyzing PC biosynthesis, attenuates the development of atherosclerosis...
  34. pmc Characterization of homocysteine metabolism in the rat kidney
    J D House
    Department of Biochemistry, Memorial University of Newfoundland, St John s, Canada
    Biochem J 328:287-92. 1997
    ..These studies indicate that factors that influence the transulphuration of homocysteine may influence the renal clearance of this amino acid...
  35. ncbi request reprint Hormonal regulation of cystathionine beta-synthase expression in liver
    Shobhitha Ratnam
    Department of Biochemistry, Memorial University of Newfoundland, St John s, Newfoundland A1B 3X9, Canada
    J Biol Chem 277:42912-8. 2002
    ..These results show that insulin has a direct role in regulating homocysteine metabolism. Altered insulin levels in diseases such as diabetes may influence homocysteine metabolism by regulating the hepatic transsulfuration pathway...
  36. doi request reprint Suckling rat pups accumulate creatine primarily via de novo synthesis rather than from dam milk
    Simon G Lamarre
    Department of Biochemistry, Memorial University of Newfoundland, St John s, Canada
    J Nutr 140:1570-3. 2010
    ..The great bulk of creatine accretion was via de novo synthesis by the pups, which imposed a substantial metabolic burden on them...
  37. ncbi request reprint Effects of diabetes and insulin on betaine-homocysteine S-methyltransferase expression in rat liver
    Shobhitha Ratnam
    Dept of Biochemistry, Memorial University of Newfoundland, St John s, NF, Canada, A1B 3X9
    Am J Physiol Endocrinol Metab 290:E933-9. 2006
    ....
  38. doi request reprint Hepatic glutamate metabolism: a tale of 2 hepatocytes
    Margaret E Brosnan
    Department of Biochemistry, Memorial University of Newfoundland, St John s, Canada
    Am J Clin Nutr 90:857S-861S. 2009
    ..Knowledge of the acinar localization of metabolic processes is essential for an appreciation of their relation to other hepatic functions and their regulation...
  39. ncbi request reprint New insights into creatine function and synthesis
    Margaret E Brosnan
    Department of Biochemistry, Memorial University of Newfoundland, St John s, NL, Canada A1B 3X9
    Adv Enzyme Regul 47:252-60. 2007
  40. ncbi request reprint Elevated tissue betaine contents in developing rats are due to dietary betaine, not to synthesis
    Kathy A Clow
    Department of Biochemistry, Memorial University of Newfoundland, St John s, NL, A1B 3X9, Canada
    J Nutr 138:1641-6. 2008
    ..We conclude that the transient increase in betaine reflects high dietary betaine and not a change in endogenous betaine synthesis...
  41. ncbi request reprint Metabolic design principles: chemical and physical determinants of cell chemistry
    John T Brosnan
    Department of Biochemistry, Memorial University of Newfoundland, St John s, Newfoundland, Canada A1B 3X9
    Adv Enzyme Regul 45:27-36. 2005
  42. ncbi request reprint Plasma homocysteine is regulated by phospholipid methylation
    Anna A Noga
    Department of Biochemistry and Canadian Institutes for Health Research Group on the Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
    J Biol Chem 278:5952-5. 2003
    ..Thus, phosphatidylethanolamine N-methyltransferase is an important source of plasma homocysteine and a potential therapeutic target for hyperhomocysteinemia...
  43. ncbi request reprint Homocysteine and cardiovascular disease: interactions between nutrition, genetics and lifestyle
    John T Brosnan
    Biochemistry Department, Memorial University of Newfoundland, St Johns, Newfouondland
    Can J Appl Physiol 29:773-80. 2004
    ..This is due to an impairment in homocysteine removal in renal disease. The role of these factors, and of modifiable lifestyle factors, in affecting methionone metabolism and in determining plasma homocysteine levels is discussed...
  44. ncbi request reprint Physiological regulation of phospholipid methylation alters plasma homocysteine in mice
    Rene L Jacobs
    Canadian Institutes of Health Research Group on the Molecular and Cell Biology of Lipids and Department of Biochemistry, University of Alberta, Edmonton, Canada
    J Biol Chem 280:28299-305. 2005
    ..These data suggest that phospholipid methylation in the liver is a major consumer of AdoMet and a significant source of plasma Hcy...
  45. ncbi request reprint Hyperglycinemia due to folate deficiency in rats: evidence for the lack of involvement of the hepatic glycine cleavage system
    Tyra M Dickson
    Department of Animal Science, University of Manitoba, Winnipeg, MB, Canada R3T 2N2
    J Nutr Biochem 16:736-42. 2005
    ....
  46. ncbi request reprint Methyl balance and transmethylation fluxes in humans
    S Harvey Mudd
    Laboratory of Molecular Biology, National Institute of Mental Health, Bethesda, MD 20892, USA
    Am J Clin Nutr 85:19-25. 2007
    ....
  47. ncbi request reprint Localization-independent regulation of homocysteine secretion by phosphatidylethanolamine N-methyltransferase
    David J Shields
    Department of Biochemistry and Canadian Institutes of Health Research Group on Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
    J Biol Chem 280:27339-44. 2005
    ..Thus, our data suggest that Hcy homeostasis is regulated concomitantly with PEMT activity but independently of PEMT localization...