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Extracellular Enzymes

Amylase hydrolyzes substrate starch
DNase hydrolyzes DNA.
Collagenase hydrolyzes substrate gellatin
Caseinase hydrolyzes casein protein (milk protein)
Lipase hydrolyzes the breakdown of tributyrin (fat)
Starch hydrolysis: result? interpretation? POSTIVE after adding iodine, media turn purple (iodine detects starch by turning purple), but for POSSITIVE: colorless around growth because: Amylase seceted by organism, starch has been broken down and is no longer present in the medium surrounding the growth.
Starch hydrolysis: result? interpretation? NEGATIVE after adding iodine, media turn purple (iodine detects starch by turning purple), but for NEGATIVE: purple still around growth, because amylase is not secreted by organism. Starch has not been broken down and is still present in the medium surround growth
What is DNA composed of? Nucleotides. Nucleotides are joined together by phosphodiester bonds
Result for DNAas positive? Growth with red color. clear area surround the growth because organism has hydrolyzed DNA
Result for DNase negative? Area surrounding the growth is still green. Organism is negative for DNA hydrolysis.
Positive for gelatin hydrolysis Liquid after 24-48hrs: collagenase positive, fast gelatin hydrolysis Solid after 24-48hr: continue incubate up to 1 wk. Liquid after 1 wk: collagenase positive, slow gelatin hydrolysis.
Negative for gelatin hydrolysis solid after 1 week incubate.
What does caseinase do? Caseinase is an enzyme that hydrolyzes casein (protein in milk) into amino acid.
Positive for casein hydrolysis clearing surrouding growth
Negative for casein hydrolysis no clearing around growth.
Positive for lipase clearing arround growth. Growth could be blue tinge because lipase hydrolyzes tributyrin.
Negative for lipase no clearing. Lipase does not hydrolyze tributyrin.
Created by: pipi1402