Respiration can be thought of as a series of oxidative and reductive actions, the intermediate steps of which are facilitated by a variety of oxidative and reductive enzymes, and the presence of respiratory enzymes is identified by the choice of special substrates or hydrogen acceptors based on their redox properties and the ability to produce a special color after the reaction.
Operation method
Simple identification experiments of plant dehydrogenases
Principle
Dehydrogenases are one of the important enzymes involved in electron and hydrogen transfer in the respiratory chain and include nicotinamide dehydrogenase and flavin dehydrogenase. The reduced form of flavin dehydrogenase can be oxidized by certain reagents, for example, methenolan interacts with flavinase to produce the following changes:
Materials and Instruments
Potato tubers Move I. Materials and equipment For more product details, please visit Aladdin Scientific website.
Warming oven Test tubes Blades Graduated test tubes Electric stove
Materials: potato tubers
Equipments: warming box, test tubes, razor blades, 2 pieces of 20ml graduated test tubes, electric stove
Drugs: 0.025% methylene blue solution, paraffin oil
Experimental steps
1. Take potato tubers peeled, cut into 20 pieces of 5mm square, divided into two groups, respectively, into two test tubes, one of the test tubes boiled for 20 minutes, and then each test tube to add 0.025% methylene blue solution, so that the height of the liquid surface more than the organization of the block of 2cm or so, and in the liquid surface of the liquid surface of each add a thin layer of paraffin oil, in order to prevent the air from contacting the methylene blue.
2. Move the test tube into the 25 ℃ temperature box, a day later to observe the solution and potato tuber changes, unboiled test tube solution will become colorless, while the other tube is still blue. Then the test tube on the liquid surface of the paraffin oil sucked off, remove the tube of potato tubers, placed on paper exposed to air, and then observe the color change, and explain the reasons for the change.