Studies on the catalytic activity of human hepatic porphobilinogen deaminase.
Porphobilinogen deaminase was purified from human hepatocytes. A variety of group specific reagents have been used to achieve site-specific modifications to evaluate the potential role of such groups in the whole catalytic cycle. Treatment with dicarbonyl reagents caused a rapid loss in activity tha...
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| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_10399712_v42_n4_p685_Mazzetti |
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todo:paper_10399712_v42_n4_p685_Mazzetti2023-10-03T15:57:37Z Studies on the catalytic activity of human hepatic porphobilinogen deaminase. Mazzetti, M.B. María Tomio, J. arginine liver enzyme porphobilinogen deaminase article catalysis enzyme activity enzyme inactivation enzyme kinetics human human cell liver cell Porphobilinogen deaminase was purified from human hepatocytes. A variety of group specific reagents have been used to achieve site-specific modifications to evaluate the potential role of such groups in the whole catalytic cycle. Treatment with dicarbonyl reagents caused a rapid loss in activity that was time and concentration dependent. Protection experiments revealed that arginine residues are involved in the binding of the substrate. Treatment with Woodward's reagent K showed the fastest inactivation of deaminase (85% in 30 sec at 30 mM) which was pH dependent and could be prevented by the presence of substrate, suggesting that deprotonated carboxylated groups from Asp/Glu are essential for catalytic activity. Kinetic analysis gave values of 0.3 sec-1 for the k3 rate constant and 8 x 10-2 M for the K(I) of the non covalent complex between deaminase-Woodward's Reagent K. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_10399712_v42_n4_p685_Mazzetti |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
arginine liver enzyme porphobilinogen deaminase article catalysis enzyme activity enzyme inactivation enzyme kinetics human human cell liver cell |
| spellingShingle |
arginine liver enzyme porphobilinogen deaminase article catalysis enzyme activity enzyme inactivation enzyme kinetics human human cell liver cell Mazzetti, M.B. María Tomio, J. Studies on the catalytic activity of human hepatic porphobilinogen deaminase. |
| topic_facet |
arginine liver enzyme porphobilinogen deaminase article catalysis enzyme activity enzyme inactivation enzyme kinetics human human cell liver cell |
| description |
Porphobilinogen deaminase was purified from human hepatocytes. A variety of group specific reagents have been used to achieve site-specific modifications to evaluate the potential role of such groups in the whole catalytic cycle. Treatment with dicarbonyl reagents caused a rapid loss in activity that was time and concentration dependent. Protection experiments revealed that arginine residues are involved in the binding of the substrate. Treatment with Woodward's reagent K showed the fastest inactivation of deaminase (85% in 30 sec at 30 mM) which was pH dependent and could be prevented by the presence of substrate, suggesting that deprotonated carboxylated groups from Asp/Glu are essential for catalytic activity. Kinetic analysis gave values of 0.3 sec-1 for the k3 rate constant and 8 x 10-2 M for the K(I) of the non covalent complex between deaminase-Woodward's Reagent K. |
| format |
JOUR |
| author |
Mazzetti, M.B. María Tomio, J. |
| author_facet |
Mazzetti, M.B. María Tomio, J. |
| author_sort |
Mazzetti, M.B. |
| title |
Studies on the catalytic activity of human hepatic porphobilinogen deaminase. |
| title_short |
Studies on the catalytic activity of human hepatic porphobilinogen deaminase. |
| title_full |
Studies on the catalytic activity of human hepatic porphobilinogen deaminase. |
| title_fullStr |
Studies on the catalytic activity of human hepatic porphobilinogen deaminase. |
| title_full_unstemmed |
Studies on the catalytic activity of human hepatic porphobilinogen deaminase. |
| title_sort |
studies on the catalytic activity of human hepatic porphobilinogen deaminase. |
| url |
http://hdl.handle.net/20.500.12110/paper_10399712_v42_n4_p685_Mazzetti |
| work_keys_str_mv |
AT mazzettimb studiesonthecatalyticactivityofhumanhepaticporphobilinogendeaminase AT mariatomioj studiesonthecatalyticactivityofhumanhepaticporphobilinogendeaminase |
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1807321488352608256 |