A Thesis submitted to the Faculty of
Medicine, University of the Witwatersrand,
Johannesburg, for the Degree of
Master of Science
JOHANNESBURG 1986 / The adenosine deaminase enzyme from a Xhosa tribesman
has been characterized. Red blood cell activity levels
were 6-9% of normal whereas his white cell ADA levels
were about 30% of normal. The enzyme's stability at 57°C
was shown to be greatly reduced suggesting a mutation
resulting in an enzyme with reduced stability in vivo.
It was concluded that the discrepancy in ADA activity
levels between red and white blood cells was due to the
red cells being anucleate.
The proband's residual ADA was found to have a
Michaelis Constant (K ) for adenosine m of 47.9 ♦ IS.BuM,
a value which is not significantly different from that
of normal ADA (51.7 ± 11.4ufl).
Red cell deoxy-ATP levels were measured and found
to be elevated two-to-three times over normal levels.
Red cells from ADA-deficient patients with severe
combined immunodeficiency (SCID) have been reported
with deoxy-ATP levels elevated about 1 000 times. It
was concluded that the slight elevation of deoxy-ATP
levels in the proband were too low to have any noticeable
effect on functions of his immune system.
Starch gel electrophoresis of red cell ADA from
members of the proband's family in conjunction with red
cell ADA activity levels suggested that both parents
carried a gei e for 'partial' ADA deficiency, both of
which had been inherited by the proband as well as one
of his sibs. Isoelectric focusing studies suggested
that the two, parental AUA partial deficiency genes
were different from one another.
It was also found that another rare allele of ADA,
possibly ADA ',was segregating within the same family
although this event appaars to be unconnected with the
ADA partial deficiency.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/17573 |
| Date | 29 April 2015 |
| Creators | Hart, Stephen Lewis |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf, application/pdf |
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