Synthesis and activity of tyrosinase in mouse skin melanocytes

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dc.contributor.advisorKidson, Susan Hen_ZA
dc.contributor.authorNkabinde, Nkosana Cyrilen_ZA
dc.date.accessioned2018-01-31T13:48:35Z
dc.date.available2018-01-31T13:48:35Z
dc.date.issued1990en_ZA
dc.description.abstractTyrosinase (E.C. 1.14.18.1) is a key enzyme in the biosynthesis of melanin. The control of melanin sythesis was explored in skin melanocytes of the following strains; wild type (C57BL/6J-C/C) (which maximally synthesize melanin at normal mammalian body temperature, Himalayan (C57BL/6J-cʰ/cʰ) (which maximally synthesize melanin at temperatures below 37°C) and albino (Balb c-c/c) (a mutant which does not synthesize melanin) The effect of a-MSH on tyrosinase activity was initially investigated. A skin culture tyrosinase assay that made it possible to measure the effect of α-MSH on the activity of this enzyme in vitro was first developed. It was found that α-MSH activated the wild type and Himalayan tyrosinase in a dose-dependent manner and that this activation did not require the de novo synthesis of new enzyme. The role of glycosylation on the wild type and particularly the Himalayan tyrosinase activity was next investigated. The results do not support, but are not in conflict with the theory that the Himalayan tyrosinase is inherently underglycosylated. Translation and transcription as additional control mechanisms of tyrosinase activity was finally investigated. The correlation between the levels of tyrosinase activity, abundance of the enzyme and the synthesis of tyrosinase mRNA in wild type, Himalayan and albino mice was determined. It was shown that the levels of newly synthesized tyrosinase and tyrosinase mRNA transcripts were higher in the wild type than in the Himalayan skin. This could account for the reduced tyrosinase activity in the Himalayan mutant at normal body temperature. Low levels of tyrosinase mRNA were found in the albino skin though there was no immunodetectable enzyme in this tissue.en_ZA
dc.identifier.apacitationNkabinde, N. C. (1990). <i>Synthesis and activity of tyrosinase in mouse skin melanocytes</i>. (Thesis). University of Cape Town ,Faculty of Health Sciences ,Division of Cell Biology. Retrieved from http://hdl.handle.net/11427/27178en_ZA
dc.identifier.chicagocitationNkabinde, Nkosana Cyril. <i>"Synthesis and activity of tyrosinase in mouse skin melanocytes."</i> Thesis., University of Cape Town ,Faculty of Health Sciences ,Division of Cell Biology, 1990. http://hdl.handle.net/11427/27178en_ZA
dc.identifier.citationNkabinde, N. 1990. Synthesis and activity of tyrosinase in mouse skin melanocytes. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Nkabinde, Nkosana Cyril AB - Tyrosinase (E.C. 1.14.18.1) is a key enzyme in the biosynthesis of melanin. The control of melanin sythesis was explored in skin melanocytes of the following strains; wild type (C57BL/6J-C/C) (which maximally synthesize melanin at normal mammalian body temperature, Himalayan (C57BL/6J-cʰ/cʰ) (which maximally synthesize melanin at temperatures below 37°C) and albino (Balb c-c/c) (a mutant which does not synthesize melanin) The effect of a-MSH on tyrosinase activity was initially investigated. A skin culture tyrosinase assay that made it possible to measure the effect of α-MSH on the activity of this enzyme in vitro was first developed. It was found that α-MSH activated the wild type and Himalayan tyrosinase in a dose-dependent manner and that this activation did not require the de novo synthesis of new enzyme. The role of glycosylation on the wild type and particularly the Himalayan tyrosinase activity was next investigated. The results do not support, but are not in conflict with the theory that the Himalayan tyrosinase is inherently underglycosylated. Translation and transcription as additional control mechanisms of tyrosinase activity was finally investigated. The correlation between the levels of tyrosinase activity, abundance of the enzyme and the synthesis of tyrosinase mRNA in wild type, Himalayan and albino mice was determined. It was shown that the levels of newly synthesized tyrosinase and tyrosinase mRNA transcripts were higher in the wild type than in the Himalayan skin. This could account for the reduced tyrosinase activity in the Himalayan mutant at normal body temperature. Low levels of tyrosinase mRNA were found in the albino skin though there was no immunodetectable enzyme in this tissue. DA - 1990 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1990 T1 - Synthesis and activity of tyrosinase in mouse skin melanocytes TI - Synthesis and activity of tyrosinase in mouse skin melanocytes UR - http://hdl.handle.net/11427/27178 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/27178
dc.identifier.vancouvercitationNkabinde NC. Synthesis and activity of tyrosinase in mouse skin melanocytes. [Thesis]. University of Cape Town ,Faculty of Health Sciences ,Division of Cell Biology, 1990 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/27178en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDivision of Cell Biologyen_ZA
dc.publisher.facultyFaculty of Health Sciencesen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherCell Biologyen_ZA
dc.subject.otherTyrosinase - biosynthesisen_ZA
dc.subject.otherMelanocytesen_ZA
dc.subject.otherMiceen_ZA
dc.titleSynthesis and activity of tyrosinase in mouse skin melanocytesen_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMSc (Med)en_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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