Athel Cornish-Bowden wrote:
> If we add to that that it is one of the few
> enzymes we can imagine life carrying on quite happily without,
> then...
Depending on one's definition of 'few' I wouldn't agree with that. In
the post-genomic, serial gene-knockout program in baker's yeast (where you
can tell by tetrad analysis) about 1 in 6 gene products are essential to the
life of that cell (their deletion is lethal) in all conditions tested. A
reasonable fraction of these are enzymes (However, I haven't yet analysed
how the the %age of genes whose deletion is lethal varies by TYPE of gene
product).
(As you may read in the paper, the score was about 1 in 8 when we submitted
the following: Oliver, S.G., Winson, M.K., Kell, D.B. & Baganz, F. (1998)
Systematic functional analysis of the yeast genome.Trends Biotechnol. 16,
373-378 [Sept issue], and yes I have seen the obvious mistake in Fig 1b
introduced by the Journal.)
BTW (re Michael's earlier post), I think [this is from memory] the concept
of 'perfection' in enzyme (TIM) catalysis was introduced by Albery rather
than by Knowles [Albery, W.J. & Knowles, J.R. (1976) Evolution of enzyme
function and the development of catalytic efficiency. Biochemistry 15,
5631-40.]
Douglas.
