Gyrase

What technique have you used for determining native denature ratio? CD? please notice when you say 25% denatured, it dose not mean 25% totally denatured and 75% are totally native. urea denatures all of your enzyme molecules! so we are not talking about your original enzyme we are talking about a new 3d structure!

Hobbz, we are not talking about reducing likelihood of some illnesses by some percents and increasing life-span for some years. we are talking about process of aging that if it is understood it can increase life span of an organism dramatically for ours I don't mean 10,20,50 years but maybe 400,800,... as I said in some worms with usually short lifespan, lowering body temp+ low calorie diet could multiply their life span if I remember correctly more than x4. As I said my knowledge is a few years old but as far as I remember first there were much enthusiasms about vitamin E but there were also some researches that questioned previous findings that vitamin E can lower risk of cancer and heart disease. we are not talking about cancer that usually appears at last stages of organism life we are talking about process of aging that if slows can multiply our life span at very least. you talked about effect of upregulated antioxidant enzymes on number of cell division in vitro. can you be more specific which enzyme, which cell, possibly refer me to abstract of the article? I especially interested about new researches. cheers, DG,

Km is constant but Vmax will increase. Of course if the enzyme has michaelis-menten kinetics at all! cheers, DG

ROS can cause cancer but not all old people die from cancer and many of cancers are known to be genetically inherited. ROS is definitely a prime suspect. maybe the price that an animal pays for, to be faster and more agile(more oxygen) is reducing life Span. All aerobic organisms had to fight the damages that they cause from the start of aerobic life but also defense mechanisms against ROS are very sophisticated and why anti oxidation chemicals like vitamin E do not have a sensible effect increasing our life span. can you think about an experiment that can shed light exactly to what extent ROS can cause aging? cheers, DG

Hello Hobbz, if your are looking for an intuitive proof rather than mathematical, then I should tell you something; when I was student I remember that I exactly had this question in my mind and whenever I asked professors this question they were giving me mathematical explanations and were accusing me that "I'm shaking and questioning foundation of logic and math" with such questions They didn't help but the conclusion that I reached to it myself is: The speed is defined as [ES]*k2, so in a fact more [ES] means faster operation so if [ES] reaches to half of its maximum concentration then speed is Vmax/2. Now to the contrary of chemical reactions there is a concentration of substrate that increasing it from that amount will not change V, we call it max at which the plot reaches a plateau, now in a chemical reaction we would expect that having the concentration of the other component [E] constant then [ES]max/2 to be reached at max/2 so km should be max/2 so we should not see km to be the same for all enzyme concentrations but the trick is in enzymes we also have k2 that removes [ES] from equation so in higher concentration of enzyme the speed is faster and removes [ES] faster so to reach [ES]max we need more concentration of more than km*2. Think about it for a while. this explanation helped me to sleep more comfortable at nights, hope it helps you too. cheers, DG

First of all Ks never change! Even if all bears of the world suddenly start belly dancing still Ks(k1, k2, k-1, km,...) remain constant hence the name K. Second Vmax depends on concentration of enzyme no argue. If you increase enzyme concentration, Vmax increases and also Vmax/2 increases but if you plot michaelis-menten plots at different enzyme concentrations and draw a perpendicular line from Km it will pass from Vmax/2 points of all plots. In michaelis menten plot we plot V against , it is possible to write an equation to relate V to [E] but it is not useful.

2 hours is too long, Tetramethylbenzidine is less stable comparing to other chromogenes like 4-aminoantipyrine.

corbelan, I don't know why you want glycophorin and what are your skills but it is relatively easy to purify you can find lots of articles in medline about purification methods of glycophorin. You can buy some from sigma,aldrich or fluka. some time ego they were independent companies but now they are a very big cartel http://www.sigmaaldrich.com

greetings, you can find mathematical proof in every biochemistry textbook, known as michaelis menten formula that proves V = Vmax ([s]/([s]+km)) you can see if you place instead of Km, V will be 1/2Vmax regards,

Hello, What do we know about aging? What are latest findings? I start but my knowledge on this issue may be a few years old ... 1- One of theories is telomere shortening that as far as I know has been shown is related to some forms of pathologic aging. But not all cells divide at the same rate, what about neurons what cause them to be lost in process of aging 2- It has been suggested that some proteins known as Heat shock proteins that help to preserve conformation of cellular proteins may be associated with aging. Their expression decrease with aging. Dose it mean if we could lower temperature of body and prevent local hyperthermia we would much longer. If I recall correctly it has been shown that in some worms lowering body temperature + very low calorie regime can multiply their life period, can this be true also for complex primates ? 3- Free radical especially oxygen, ROS(Reactive Oxygen Species) is another prime suspect. Some damages to DNA may be unrepairable and accumulate overtime, also damages to cell membrane can be important. But Cells have very sophisticated defense mechanisms against ROS. If we would supply huge amount of none toxic anti oxidants could it multiply our life period? It has been recommended to use extra amount of anti oxidants like vitamin E as supplements but it had not huge effect on humans' life period. regards,

1- Why you chose d? some hydrogen bondings take place between residues far apart in primary structure, how do you think these far residues are supposed to find each other? 2- why not 3- in watery solutions all hydrophobic residues tend to go inside the tertiary structure and maximizing hydrophobic interactions. Hydrogen bonding between surface residues and water is also very important.(I'm not sure if you have translated it correctly or not but rotation per se is not a determining factor but if it means going toward center and maximizing hydrophobic interactions then it is c)

One thing that I wonder is if someone dose a research work in such a home-laboratory and reach a very interesting results, can he publish it by his own name? I mean all articles usually associated to some universities, labs. Do journals publish result of a scientific work done in home-lab?

mrlucky0, to answer your question K1 & k-1 have nothing to do with k2 but as others suggested km can be interpreted as enzyme-substrate affinity when k2<<k-1. regards,