| 词条 | Invertase |
| 释义 |
| EC_number = 3.2.1.26 | CAS_number = 9001-57-4 | IUBMB_EC_number = 3/2/1/26 | GO_code = | image = | width = | caption = }}Invertase is an enzyme that catalyzes the hydrolysis (breakdown) of sucrose (table sugar) into fructose and glucose.[1][2] Alternative names for invertase include {{EC number|3.2.1.26}}, saccharase, glucosucrase, beta-h-fructosidase, beta-fructosidase, invertin, sucrase, maxinvert L 1000, fructosylinvertase, alkaline invertase, acid invertase, and the systematic name: beta-fructofuranosidase. The resulting mixture of fructose and glucose is called inverted sugar syrup. Related to invertases are sucrases. Invertases and sucrases hydrolyze sucrose to give the same mixture of glucose and fructose. Invertases cleave the O-C(fructose) bond, whereas the sucrases cleave the O-C(glucose) bond.[3] For industrial use, invertase is usually derived from yeast. It is also synthesized by bees, which use it to make honey from nectar. Optimal temperature at which the rate of reaction is at its greatest is 60 °C and an optimum pH of 4.5.[3] Typically, sugar is inverted with sulfuric acid.{{Dubious |Sulfuric acid |reason=yet this is mentioned nowhere on the Inverted sugar syrup page (to which "Inverted sugar" redirects |date=May 2016}} Applications and examplesInvertase is expensive, so it may be preferable to make fructose from glucose using glucose isomerase, instead.{{citation needed|date=October 2013}} Chocolate-covered cherries,[4] other cordials, and fondant candies include invertase, which liquefies the sugar. Once the candy is manufactured, it needs at least a few days to a few weeks in storage so the invertase has time to break down the sucrose.[5] InhibitionUrea acts as a non-competitive inhibitor of invertase, presumably by breaking the intramolecular hydrogen bonds contributing to the tertiary structure of the enzyme.[6][7]See also
References1. ^{{cite book | chapter = Invertases | title = The Enzymes | vauthors = Myrbäck K |year = 1960 |volume = 4 |pages = 379–396 | veditors = Boyer PD, Lardy H, Myrbäck K |edition = 2nd |publisher = Academic Press |location = New York }} 2. ^{{cite journal | vauthors = Neumann NP, Lampen JO | title = Purification and properties of yeast invertase | journal = Biochemistry | volume = 6 | issue = 2 | pages = 468–75 | date = February 1967 | pmid = 4963242 | doi = 10.1021/bi00854a015 }} 3. ^1 {{cite book | first1 = Hubert | last1 = Schiweck | first2 = Margaret | last2 = Clarke | first3 = Günter |last3 = Pollach | chapter = Sugar | title = Ullmann's Encyclopedia of Industrial Chemistry | date = 2007 | publisher = Wiley-VCH | location = Weinheim | doi = 10.1002/14356007.a25_345.pub2 }} 4. ^{{cite web|last=LaBau|first=Elizabeth | name-list-format = vanc |title=Chocolate-Covered Cherries|url=http://candy.about.com/od/fruitnutcandy/r/choccherry.htm|publisher=About.com Candy|accessdate=December 6, 2012}} 5. ^{{cite web | last = LaBau | first = Elizabeth | name-list-format = vanc | url = http://candy.about.com/od/candyglossary/g/What-Is-Invertase.htm | title = What is Invertase? | work = About.com | access-date = 10 April 2015 }} 6. ^{{Cite journal|last=Chase|first=Aurin M.|last2=Von Meier|first2=Hildegard C.|last3=Menna|first3=Vincent J.|date=February 1962|title=The Non-Competitive Inhibition and Irreversible Inactivation of Yeast Invertase by Urea|url=https://doi.org/10.1002/jcp.1030590102|journal=Journal of Cellular and Comparative Physiology|volume=59|issue=1|pages=1–13|doi=10.1002/jcp.1030590102|issn=0095-9898}} 7. ^{{Cite journal|last=Rajagopalan|first=K. V.|last2=Fridovich|first2=Irwin|last3=Handler|first3=Philip|date=1961-04-01|title=Competitive Inhibition of Enzyme Activity by Urea|url=http://www.jbc.org/content/236/4/1059|journal=Journal of Biological Chemistry|volume=236|issue=4|pages=1059–1065|issn=0021-9258|pmid=13739212}} External links
3 : EC 3.2.1|Food additives|E-number additives |
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