Other than that highly useful occurence, I had a meeting with both my supervisors (Vera was back in Norwich partly to speak with someone else). Vera and I went through the stuff that confused me so much last week. I'd not got it wrong, and I was right both about the definition of specific activity (ug collagen cleaved per minute per nmol collagenase, in this case) and about how to calculate it on Excel. The problem was actually due to the set-up of my experiment - which I'd designed to do a different collection of calculations on. For calculating the kcat and KM directly it didn't matter what the substrate concentration was, as when you do a Lineweaver-Burke plot (1/v against 1/[S]) it'll be linear whatever the [S] is. However when calculating the specific activity, if you want to compare it between experiments, and between assay systems, you need to have the concentration of substrate at levels where it saturates the enzyme, and then the rate approaches Vmax. So it doesn't change with differing [S], so you get a single value for the specific activity. We've decided for the paper to go with quoting comparative specific activities, determined at [S]=1uM. Which ought to be ok. Now all I have to do is alter the text of the paper to reflect all of that and mail it back round to people. Then hopefully after that Gill'll have a minmum to add (I know there's a paper she thinks we ought to reference more that we missed before). Then we can send it back to JBC and hopefully it'll be accepted this time. If not, then we have a list of experiments to do to try and get it in again, but I'll do them if and when I have to - which won't be till after I'm back in the lab full time.
Well, I get the feeling that'll've lost everybody, but I rarely actually talk about what I'm actually doing in my work, and I was all pleased to have got that sorted. And I wasn't wrong, or confused - simple arithmetic conversions of things have a tendancy to trip me up, I can easily reason myself into a circle and end up not know what the hell I'm doing! But if I can turn it into algebra, then I'm fine. I work out how much enzyme to put into experiments (given stock concentration, total volume and concentration I want) by turning it into a simple algebraic equation and solving for x. I no longer have to do that every time, but if I do get confused then I know why I'm doing what I'm doing and how to sort it out. Being like that really annoys me sometimes though.
Getting home again was tedious - it took over 3 hours rather than the 2 it should, just coz I screwed up the connections, I thought there was a 1440 train, but it still doesn't exist (one of the final 4 relics of the great hoo-ha we've had with the railways). So I spent just under an hour on Norwich station. Looked in the WHSMiths for the magazines we wanted, but no new PS2 mag, no new Linux mags, no new BBC music mag :( SO I bought a Dick Francis book instead as a piece of cheap fluff!
Random thought of the day - why do I have to restrain myself from starting every paragraph with the word 'Well'. Weird.
PS Yeah ok, so the mood and the music don't seem to fit, but both are true :)