A basal level of human liver porphobilinogen deaminase of 3.66 units/g wet weight was found in adult tissue. Activity in neonatal liver was at least three fold higher. Physico-chemical studies revealed that the enzyme has the approximate form of a symmetrical molecule and exhibits hyperbolic kinetics with a Km value of 3.6 μM at pH 7.6. Two ionizable groups with pK values of 7.35 and 8.90 are prominent for catalysis. A set of pI (5.8 - 4.9) were observed under different conditions. Results demonstrate the existence of a single protein differentially charged with multiple molecular forms in adult liver.
| Documento: | Artículo |
| Título: | Kinetic and molecular parameters of human hepatic porphobilinogen deaminase |
| Autor: | Mazzetti, M.B.; Tomio, J.M. |
| Filiación: | Departamento de Quimica Biologica, Facultae de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellon 2, Buenos Aires 1428, Argentina |
| Palabras clave: | liver enzyme; porphobilinogen deaminase; article; human; human cell; priority journal; Adult; Human; Hydrogen-Ion Concentration; Hydroxymethylbilane Synthase; Infant, Newborn; Isoelectric Focusing; Kinetics; Liver; Support, Non-U.S. Gov't |
| Año: | 1990 |
| Volumen: | 21 |
| Número: | 3 |
| Página de inicio: | 463 |
| Página de fin: | 471 |
| Título revista: | Biochemistry International |
| Título revista abreviado: | BIOCHEM. INT. |
| ISSN: | 01585231 |
| CODEN: | BIIND |
| CAS: | Hydroxymethylbilane Synthase, EC 4.3.1.8 |
| Registro: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_01585231_v21_n3_p463_Mazzetti |
