Repository logo
 

Redox properties of cathepsin B in relation to its activity in vivo.

dc.contributor.advisorDennison, Clive.
dc.contributor.authorPillay, Che Sobashkar.
dc.date.accessioned2013-10-21T06:53:50Z
dc.date.available2013-10-21T06:53:50Z
dc.date.created1999
dc.date.issued1999
dc.descriptionThesis (M.Sc.)-University of Natal, Pietermaritzburg, 1999.en
dc.description.abstractThe main site for protein degradation along the endosomal pathway is believed to be the late endosome. Lysosomes are thought to be storage organelles that, when necessary, inject proteases into the late endosome. It was hypothesised that differences in the lumenal redox environments between the two organelles could be responsible for their functional differences. In an attempt to quantify this potential difference, the lysosomal cysteine protease cathepsin B was isolated by an improved purification procedure. Several intracellular reducing agents were used to activate cathepsin B, the most effective being cysteine. Cysteine was used to activate cathepsin B under various pH conditions in order to model endosomal conditions. An inverse relationship was found between the pH and the concentration of cysteine required to activate cathepsin B. This suggested that cathepsin B may have an optimal redox potential. In order to determine this potential, cysteinexystine redox buffers were made up and used in determination of the activity of the enzyme against a synthetic and a whole protein substrate (haemoglobin). No distinct redox potential could be determined using either substrate, but it was found that cystine stimulated proteolysis of haemoglobin. A similar stimulatory effect was observed for cathepsin D and papain hydrolysis of haemoglobin. This effect is possibly due to the ability of cystine to promote substrate structure, effectively increasing the substrate concentration. These findings and other results obtained from the literature have been used to create a model of how proteolysis may be regulated along the endosomal system.en
dc.identifier.urihttp://hdl.handle.net/10413/9781
dc.language.isoen_ZAen
dc.subjectCathepsin B.en
dc.subjectProteolytic enzymes.en
dc.subjectTheses--Biochemistry.en
dc.titleRedox properties of cathepsin B in relation to its activity in vivo.en
dc.typeThesisen

Files

Original bundle

Now showing 1 - 1 of 1
Loading...
Thumbnail Image
Name:
Pillay_Ché_S_1999.pdf
Size:
18.96 MB
Format:
Adobe Portable Document Format
Description:
Thesis.

License bundle

Now showing 1 - 1 of 1
No Thumbnail Available
Name:
license.txt
Size:
1.64 KB
Format:
Item-specific license agreed upon to submission
Description: