Bitamin A
Gabatar da ɗan gajeren lokaci
Vitamin A ya ƙunshi bitamin A1 da A2. Bitamin A1 da A2 suna da tsari iri ɗaya) Ana iya haɗa Retinol daga beta-carotene da aka samo daga tsire-tsire. A ƙarƙashin catalysis na β-carotene-15, 15'-peroxide (bioxygenase) a cikin jiki, ana iya canza β-carotene zuwa ƙwayoyin halitta guda biyu na retinaldehyde (ratinal), da retinaldehyde a cikin reductase. Ana rage shi zuwa retinol a ƙarƙashin aikin. Saboda haka, beta-carotene kuma ana kiransa bitamin A.
Sifofin sinadarai
Vitamin A foda ne mai launin rawaya mai launin shuɗi ko kuma mai siffar crystalline, wanda ba ya narkewa a cikin ruwa da glycerine, kuma yana narkewa a cikin yawancin abubuwan narkewa na halitta kamar alcohols, ethers, hydrocarbons da halogenated hydrocarbons. Sunan sinadarai na jikin bitamin A - retinol shine all-trance 3,7-dimethyl-9-(2,6,6-trimethyl-1-cyclohexene-1)-2,4,6,8-nontetraene-1-ol, tare da haɗin gwiwa guda biyu guda huɗu a sarkar gefe.
Ayyukan jiki da tasirinsu
Vitamin A bitamin ne mai narkewar mai, kuma aikinsa na jiki galibi yana cikin nau'in retinoic acid. Carotene muhimmin tushen bitamin A ne. Mafi yawan bitamin A a cikin carotene shine beta-carotene. Yawan shan bitamin a cikin hanjin ɗan adam shine kusan kashi ɗaya cikin shida na bitamin A. Ana adana Vitamin A galibi a cikin hanta a cikin jiki, wanda ya kai kusan kashi 90% zuwa 95% na jimlar adadin, kuma ƙaramin adadin yana adanawa a cikin kyallen adipose. Vitamin A yana taka muhimmiyar rawa a cikin aikin metabolism na jikin ɗan adam.
