Vitamin A
Qhia luv luv
Vitamin A muaj xws li cov vitamins A1 thiab A2. Cov vitamins A1 thiab A2 zoo sib xws hauv cov qauv) Retinol tuaj yeem tsim los ntawm cov nroj tsuag beta-carotene. Nyob rau hauv lub catalysis ntawm β-carotene-15, 15'-peroxide (bioxygenase) hauv lub cev, β-carotene tuaj yeem hloov pauv mus rau hauv ob lub molecule ntawm retinaldehyde (ratinal), thiab retinaldehyde hauv reductase Nws raug txo kom retinol nyob rau hauv qhov kev ua ntawm. Yog li ntawd, beta-carotene kuj tseem hu ua vitamin A.
Cov khoom siv tshuaj lom neeg
Vitamin A yog cov siv lead ua daj lossis cov hmoov crystalline, tsis yaj hauv dej thiab glycerine, thiab yaj hauv feem ntau cov kuab tshuaj organic xws li cawv, ethers, hydrocarbons thiab halogenated hydrocarbons. Lub npe tshuaj lom neeg ntawm lub cev ntawm vitamin A - retinol yog all-trance 3,7-dimethyl-9-(2,6,6-trimethyl-1-cyclohexene-1)-2,4,6,8-nontetraene-1-ol, nrog 4 conjugated ob chav bonds ntawm nws cov saw sab.
Kev ua haujlwm ntawm lub cev thiab cov teebmeem
Vitamin A yog ib hom vitamin uas yaj tau hauv roj, thiab nws lub luag haujlwm feem ntau yog nyob rau hauv daim ntawv ntawm retinoic acid. Carotene yog ib qho tseem ceeb ntawm vitamin A. Cov vitamin A uas muaj zog tshaj plaws hauv carotene yog beta-carotene. Tus nqi nqus hauv tib neeg txoj hnyuv yog li ib feem rau ntawm cov vitamin A. Vitamin A feem ntau khaws cia rau hauv daim siab hauv lub cev, suav txog li 90% txog 95% ntawm tag nrho cov nyiaj, thiab me me khaws cia rau hauv cov ntaub so ntswg adipose. Vitamin A ua lub luag haujlwm tseem ceeb heev hauv kev ua haujlwm ntawm tib neeg lub cev.
