I determine the enzyme activity in fish liver and muscle by using the diagnostic kit. This mentioned in kit that after calculation the activity is in IU/L, since the kit is designed for serum analysis. I used the same kit for enzyme analysis in tissues, therefore I need to convert the unit IU/L to mg/g. Could anybody help me out?
You can convert the IU/L of your enzyme into IU/g wet fresh tissues very easily knowing the volume of extract you obtained from 0.2g of tissues, dividing the total units (IU/Lxvolume of extract) by 0.2. You should also measure the protein concentration in your samples. At this point you can also express your results as IU/mg of proteins, dividing IU/L by mg/L of total proteins. The usual protocols for protein determination give you the mg/ml of proteins but you can easily calculate the mg/L. I think that to express the enzyme activity in a crude extract as U/mg of total protein is better than U/g of fresh tissue.
1 IU is the activity ro transform 1 micromol/min.
something is wrong to have mg/g. mg/g is just a mass percentage.
I suppose that you want to know IU/mg enzyme or something like that.
You need to know the turnover number of the enzyme, its molecular weight and its purity (Is the enzyme pure or contaminating with other proteins in a raw extract?
The Unit of enzyme activity is the amount of the biocatalyst able to release 1 micromol of product per minute at 'standard conditions' (in theory the optimum set of pH, temperature, in the presence of cofactors, etc.). As Francisco wrote before, probably you would be interested in knowing the activity expressed as U/mg, the so called specific activity, or U/mL, also a frequent expression.
Sir, actually what i did is i take 0.2g tissue and make homogenate in 2 ml phosphate buffer, centrifuge and then collect supernatant. From this supernatant i proceed the experiment as per the protocol given in the pack insert of the kit. I did this to determine the level of enzyme activity in that tissue. I induced the fish therefore want to know the enzyme activity level in serum and a tissue. I have no problem with serum since the activity level measured in the IU/L as mentioned in the kit. The problem is with tissue because i take 0.2 g fresh weight to make homogenate. Therefore i want to convert enzyme activity of tissue in IU/mg fresh tissue or IU/g fresh tissue. To compare it with other parameters like total prrotein, albumin etc.
Sir,
Would you please tell me how is turnover number of the enzyme, its molecular weight and its purity (Is the enzyme pure or contaminating with other proteins in a raw extract? is calculated?
You can convert the IU/L of your enzyme into IU/g wet fresh tissues very easily knowing the volume of extract you obtained from 0.2g of tissues, dividing the total units (IU/Lxvolume of extract) by 0.2. You should also measure the protein concentration in your samples. At this point you can also express your results as IU/mg of proteins, dividing IU/L by mg/L of total proteins. The usual protocols for protein determination give you the mg/ml of proteins but you can easily calculate the mg/L. I think that to express the enzyme activity in a crude extract as U/mg of total protein is better than U/g of fresh tissue.
I have a doubt, please help me.
It's part of oral digestion step.
Human salivary a-amylase(EC 3.2.1.1) is added to achieve 75 U mL-1 in the final mixture, So how many mg or microgram of this a-amylase I should need to add to the water to make this 75 U mL-1 in the final mixture, my sample weight is 5g.
Respected All
Hope you find this text in good health ,i am facing the probem .i have performed the same experiment to assay the enzyme activity but i have estimated from serum .and have found some papers who have mentioned in mol/h/mg protein.
my value in IU/L is 26.10 IU/L while they have mentioned the value as 0.370 +- 0.02 .mol/h/mg protein. how close or how my values are with the values mentoined.
because both values of the control specimen and specimen is same ,and both have estimated from the serum
Thanks
Dear Mehjabeen,
You may follow this online tool to calculate enzyme units in to mg or mL ok
http://www.physiologyweb.com/calculators/units_per_volume_solution_concentration_calculator.html
Mohiuddin Yatoo - did you find the answer? Actually I am also facing the same problem, control value similar with the highest concentration during Alkaline phosphatase study.
Thank you Maria Grazia Tozzi for the elaborative explanation, great helpful.
It is necessary to know the molecular weight of consumed substrate or production of enzymatic reaction, also, the density of solution. For measuring the density of solution, you can use a pycnometer. By multiplying the enzyme unit by molecular weight of consumed substrate or production and the density of the solution, you can change (U/L) to mg/g.
1 Units/mL = 10-6 mol (consumed substrate or production) × Molecular weight (g/mol) (of consumed substrate or production) ×10-3(mg/g)× density of solution (g/ml) /(time × volume of reaction) × time
- Badges
- Science topic
- Similar topics
- Biological Science
- Biochemistry
- Enzymology
- Enzymes