L-histidine ammonia-lyase (histidase) was encapsulated within cellulose nitrate artificial cells, and its kinetic parameters were evaluated. Microencapsulated histidase had an apparent activity of approximately 50% of the activity of histidase in solution. Encapsulation did not alter the K$ sb{ rm M}$ of histidase. The K$ sb{ rm M}$ of histidase solution and the K$ sb{ rm M}$ apparent of microencapsulated histidase were both 20mM. Encapsulation of histidase resulted in increased stability of enzymatic activity of storage temperatures of 4$ sp circ$C and 37$ sp circ$C. At 37$ sp circ$C histidase solution reached 50% of its original activity after 9.5 days of storage, while microencapsulated histidase reached the same level after 15 days. At 4$ sp circ$C histidase solution had 63% of its original activity after 21 days of storage, while encapsulated histidase had 95%. In vitro experiments to evaluate the feasibility of microencapsulated histidase for possible experimental therapy in histidinemia were carried out. These experiments evaluated the effectiveness of encapsulated histidase in depleting histidine. Three different volume ratios of histidase loaded artificial cells to substrate solution were tested. A ratio of 1:100 allowed 25% histidine depletion after 120 hours. A 1:50 ratio allowed 35% histidine depletion after 72 hours. A 1:25 ratio allowed 40% histidine depletion after 24 hours.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.59405 |
| Date | January 1989 |
| Creators | Khanna, Rajesh |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Physiology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001068859, proquestno: AAIMM63577, Theses scanned by UMI/ProQuest. |
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