“ A particular enzyme will generally only
Enzymes are used not only for nitrogen availability , but for a wide variety of chemical reactions , both internal and external to plants .”
help one particular chemical reaction . This is because each enzyme molecule has a particular shape that only fits with one or two other target molecules . It binds to the other molecules , a change occurs , and then it breaks off again . The cycle repeats when it encounters new target molecules . Some enzymes take two molecules and recombine them , some take large molecules and split them . The molecules that an enzyme acts upon are known as substrates , and the area of the enzyme molecule that they fit into is known as the enzyme ’ s active site . For example , urease is an enzyme that helps convert urea — CO ( NH 2 ) 2 — and water ( H 2O ) into carbon dioxide ( CO 2 ) and ammonia ( NH 3 ). A molecule of urease binds to molecules of urea and water , and a reaction occurs so that when they separate they form carbon dioxide , ammonia , and the original urease molecule , which can then bind to other urea and water molecules . Plants cannot take up urea directly , so urease is one of the most important enzymes in the steps needed to make the nitrogen in urea available . Two other enzymes are used to convert the ammonia into nitrites :
• Ammonia monooxygenase is an enzyme that converts ammonia ( NH 3 ) and oxygen ( O ) into hydroxylamine ( NH 2OH ).
• Hydroxylamine oxidase is an enzyme used to convert hydroxylamine ( NH 2OH ) into nitrite ( NO 2 ) and water ( H 2O ).
Additionally , while some plants can feed directly from nitrites , some prefer nitrates . Nitrite oxidoreductase is an enzyme that converts the nitrite ( NO 2 ) into nitrate ( NO 3 ). Each reaction has its own enzyme , which is why having the correct enzymes present for the desired reactions is critical . Enzymes are used not only for nitrogen availability , but for a wide variety of chemical reactions , both internal and external to plants ( and all other forms of life ).
Internally , enzymes in plants are used for processes such at photosynthesis . Externally , plant roots naturally express enzymes to assist with nutrient uptake . There are other garden uses for enzymes as well . For example , some enzymes will act as insecticides , dissolving the insect ’ s waxy protective coating , known as its cuticle , and exposing its exoskeleton . Others can help protect plants from molds and bacteria . While most enzymes will only accept a particular set of molecules to act on , they can occasionally be fooled by similarly shaped molecules . For example , glyphosate is an herbicide that kills by binding to needed enzymes , interfering with their function . Since the glyphosate is bound to the enzyme molecules , they cannot bind normally to other molecules , inhibiting chemical reaction . Other factors that can be used to inhibit enzyme function are temperature ( enzymes cannot tolerate the high temperatures used in cooking , which begins to explain the raw food diet movement in humans ) and pH . Fortunately , enzymes can tolerate a broad pH range of 3.0 to 9.0 .
The developers of today ’ s plant supplements have cultivated specific enzymes that can boost plant growth and health depending on the growth cycle . For help selecting the right type for your set-up , as well as dosage instructions , ask the people behind the counter at your local hydroponics shop , or check out past issues of Maximum Yield available at maximumyield . com .
Grubbycup has been an avid indoor gardener for more than 20 years . His articles were first published in the United Kingdom , and since then his gardening advice has been published in multiple languages . He is also considered one of the world ’ s leading authorities on crochet hydroponics .
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