Alpha vs Beta Glucose
Glucose yog chav tsev ntawm carbohydrate thiab qhia cov yam ntxwv tshwj xeeb ntawm carbohydrate. Glucose yog monosaccharide thiab txo cov suab thaj uas yog cov khoom tseem ceeb ntawm photosynthesis hauv cov nroj tsuag. Chlorophylls tsim cov piam thaj thiab oxygen siv cov pa roj carbon thiab dej. Yog li, lub hnub ci yog tsau rau hauv tshuaj zog los ntawm cov piam thaj. Tom qab ntawd cov piam thaj ntxiv rau hauv cov hmoov txhuv nplej siab thiab khaws cia rau hauv cov nroj tsuag. Hauv kev ua pa, cov piam thaj tau tawg mus rau ATP thiab muab lub zog rau cov kab mob muaj sia uas ua rau carbon dioxide thiab dej ua cov khoom kawg ntawm kev ua pa. Glucose tuaj yeem pom hauv tsiaj thiab tib neeg, hauv lawv cov ntshav.
Glucose yog rau cov pa roj carbon monoxide lossis hu ua hexose. Cov mis ntawm cov piam thaj yog C6H12O6,thiab cov mis no muaj ntau rau lwm cov hexoses Ib yam nkaus. Glucose tuaj yeem ua rau hauv lub rooj zaum cyclic thiab hauv daim ntawv saw.
Vim cov piam thaj muaj aldehyde, ketone thiab cawv ua haujlwm pab pawg nws tuaj yeem hloov pauv tau yooj yim rau hauv daim ntawv ncaj nraim mus rau daim ntawv voj voog. Lub tetrahedral geometry ntawm cov pa roj carbon monoxide ua rau rau lub nplhaib ruaj khov. Hydroxyl pab pawg ntawm cov pa roj carbon tsib nyob rau hauv cov saw ncaj yog txuas nrog carbon ib tug ua hemiacetal daim ntawv cog lus (Mcmurry, 2007). Yog li cov pa roj carbon ib hu ua anomeric carbon. Thaum cov piam thaj raug xam rau hauv fischer projection, qhov no pawg hydroxyl ntawm asymmetric carbon yog kos rau ntawm txoj cai thiab hu ua D-qabzib. Yog hais tias pawg hydroxyl ntawm asymmetric carbon nyob rau sab laug nyob rau hauv lub fischer projection, nws yog L-qabzib. D-qabzib muaj ob lub sterioisomers hu ua alpha thiab beta sib txawv ntawm kev sib hloov. Hauv kev sib tov, ob daim ntawv no tuaj yeem hloov mus rau ib leeg thiab ua kom muaj kev sib npaug. Txoj kev no hu ua mutarotation.
Alpha Glucose
Kev npaj ntawm cov atom hauv qhov chaw ntawm cov piam thaj molecule yog qhov tseem ceeb thaum txiav txim siab txog cov tshuaj lom neeg. Alpha thiab beta glucose yog stereoisomers. Lub (1-4) glycosidic daim ntawv cog lus ntawm ob α-D-glucose molecules tsim cov disaccharide hu ua m altase. Bonding ntau ntawm α-D-glucose molecules α-(1-4) glycosidic bond starch yog tsim, uas muaj amylopectin thiab amylose. Lawv tuaj yeem tawg yooj yim los ntawm enzymes.
YBeta Glucose
Ob ob β-D- qabzib molecules yog khi nrog (1-4) glycosidic daim ntawv cog lus ua cellobiose, thiab ntxiv ua cellulose uas nyuaj rau tawg los ntawm enzymes. Daim ntawv beta ruaj khov dua li daim ntawv alpha; Yog li hauv kev sib tov, tus nqi ntawm β-D- qabzib yog ob feem peb ntawm 20 °. Txawm hais tias ob daim ntawv isomeric no zoo ib yam hauv cov ntawv theem pib, lawv tsis zoo sib xws hauv lub cev thiab tshuaj lom neeg.
Dab tsi yog qhov txawv ntawm Alpha Glucose thiab Beta Glucose?
• Lawv txawv ntawm kev sib hloov, α- D- qabzib muaj [a]D20 ntawm 112.2° thiab β-D-glucose muaj
[a] D20 of 18.7°.
• Daim ntawv beta ruaj khov dua li daim ntawv alpha, yog li hauv qhov sib xyaw ntawm β-D- qabzib siab dua α-D-glucose.
• Lub (1-4) glycosidic daim ntawv cog lus ntawm ob α-D-glucose molecules tsim cov disaccharide hu ua m altase thaum ob lub β-D-glucose molecules raug khi nrog (1-4) glycosidic bond ua cellobiose.
• Cov hmoov txhuv nplej siab, uas yog tsim nrog α-D-glucose, yooj yim tawg los ntawm enzymes, whereas cellulose tsis tuaj yeem yooj yim tawg los ntawm enzymes.
• Cellulose, uas yog ib qho polymer ntawm β-D-glucose, yog cov khoom siv thiab cov hmoov txhuv nplej siab yog cov zaub mov cia hauv cov nroj tsuag.
