Arun River length

The Arun River (Nepali: अरुण नदी) is a largest trans Himalayan and trans-boundary river (Nepal, China) and is part of the Kosi or Saptakoshi river of Nepal. The Arun is the largest river passing through Nepal and also has the greatest snow and ice-covered area of any Nepalese river basin. The River runs 510 Km from its origin before merging in Saptakoshi river after collecting water from 36,000 Sq. Km catchment area with North to south alignments. The altitude variation of river is 150 meter to 8,470 meter. The Arun drains more than half of the area contributing to the Saptakoshi river system but provides only about a quarter of the total discharge. The river has enormous hydroelectricity power with clean and high dense water with estimated hydroelectricity capacity of 1185 megawatt at six sites, where 900 megawatts Arun III Hydroelectricity project is under construction.

Arun river at Leguwa, junction of Dhankuta, Sankguwasabha and Bhojpur district of Nepal. 

Date: 2016/11/4

Determination of Vmax and Km value of α-amylase

Enzymes are the catalyst of biological system and are extremely efficient and specific as catalysts. In fact, typically an enzyme accelerates the rate of a reaction by factors of at least a million compared to the rate of the same reaction in the absence of enzymes.

Michaelis - Menten equation:

V_{o =} Initial reaction velocity

V_max = Maximum velocity

K_m = Michaelis constant

[S] = Substrate concentration.

Enzyme catalyzed reaction model.

K_m is the characteristic of an enzyme and its particular substrate and reflects the affinity of the enzymes for the substrate. K_m is numerically equal to the substrate concentration at which the reaction velocity is equal to ½ V_max. K_m does not vary with the concentration of enzymes.

i.                    Small K_m – A numerically small (low) K_m reflects a high affinity of the enzymes for substrate because a low concentration of substrate is needed to half saturate the enzymes.

ii.                  Large K_m – A numerically large (high) K_m reflect a low affinity of the enzymes for substrate.

Material Required:

      1.     Enzymes / Saliva

2.     Spectrophotometer

3.     Starch solution- 2% (stock), working – 0.1- 2%

4.     0.1 HCL

5.     Iodine solution

6.      Potassium phosphate buffer, pH – 7.0

    Procedure

1.         Prepared the varied concentration of soluble starch substrate of 0.01, 0.025, 0.05, 0.1, 0.3, 0.5, 0.7, and 1.0 mg/ml from the starch stock solution from stock solution - total volume 8 ml.

2.         Add 1 ml of amylase solution to each of the test tube to start the reaction.

3.         Incubate at 37⁰C for exactly 10 min.

4.         Stop the reaction after exctly 10 min by adding 1 ml of 0.1 N HCL.

5.         Add 0.1 ml iodine solution.

6.         Take absorbance at 546 nm.

7.         Plot the graph with absorbance or V in Y axis and concentration of substrate in X-axis and determine Vmax and Km.

Or

               By Lineweaver Burk double reciprocal plot taking 1/[S] in X-axis and 1/V in Y-axis.