Summary to essay on topic "Micronutrien metabolism past and present (synthesis of vitamin A from beta carotene)"
Vitamin A, derived form provitamin A carotenoids, mainly beta-carotene 15, 15-monooxygenases (EC 22.214.171.124). Vitamin A (retinol) is an essential nutrient needed in small amounts by humans and is necessary for vision, cellular differentiation, growth, reproduction, bone development and immune system actions…
Download file "Micronutrien metabolism past and present (synthesis of vitamin A from beta carotene)" to see previous pages...
In addition, the evolution of the recommended dietary intakes of vitamin A will be discussed.
Elmer V. McCollum and M. Davis discovered vitamin A during 1912-1914. In 1913, Yale researchers, Thomas Osborne and Lafayette Mendel discoveredthat butter contained a fat-soluble nutrient soon known as vitamin A. Let us write or edit the essay on your topic "Micronutrien metabolism past and present (synthesis of vitamin A from beta carotene)" with a personal 20% discount.. Try it now Scientist of this era had determined that there was vitamin A activity from yellow pigmentation in plants that was similar to the yellow in butterfat. Early researchers went on to deny the possibility of a relationship between yellow coloration in plants and vitamin A activity based on findings from Palmer and Eccles, 1914. Palmer and Eccles achieved success in rearing chickens and rats up with diets almost devoid of carotene. In addition, Stephenson  found that butter fat could be completely stripped of color by charcoal without losing its retinol activity.
It was not until 1929 when the link between carotene and vitamin A activity was reestablished. Thomas Moore in 1929 continued research between carotene and vitamin A activity in rats from carrot root. In Moore's experiment test rats were fed a vitamin A restricted diet until definite signs of deficiency become obvious, Xerophthalmia (night blindness) and slowed growth. Fresh carrot root cut into pieces of 50, 100 or 200 mg. were added to the rodents daily intake. In all rats receiving 200 or 100 mg. of carrot xerophthalmia was cured and steady growth was resumed. In one rat receiving 50 mg. of carrot no response was observed.
In addition, the experiments carried out by Moore in 1929 (T, 1929) confirmed the appearance of vitamin A in liver upon the oral dose of carotene. It was assumed that conversion occurred in the liver but direct evidence to prove the fact was not known.
In 1931, the first claim of the conversion "in vitro" was brought into account from experiments by Olcott and McCann. They incubated carotene in an enzyme preparation, carotenase, for 24 hours. The product of this experiment became colorless with an absorption band at 3280 under specrspoic examination. The results of this experiment were not duplicated in subsequent procedures when the carotenase had been deactivated by heat. There was evidence that carotene went through some sort of enzymatic process but the specifics were still unknown.
Since the early 1900's much has evolved in our knowledge of how -carotene is converted into vitamin A. Olson JA in 2008 discussed the Provitamin A of carotenoids with respects to the conversion of -carotene into vitamin A. Two pathways have been suggested for the conversion of carotenoids to vitamin A in mammals, central cleavage and eccentric cleavage. -carotenoid-15-15-dioxygenase convert -carotene into two molecules of retinal in good yield. The reaction requires molecular oxygen but, is inhibited by sulphydryl-binding and iron binding reagents. This enzyme is responsible for cleavage of most provitamin A carotenoids to retinal. The excentric cleavage occurs in plants and some microorganism and might also occur in mammals. In Microcystis species, there is a highly specific and essential stochiometric conversion of -carotene to cyclocitral and to crocetin-dial. But, till this report was published no mammalian carotenoid dioxygenase with excentric bond specificity was identified and characterized. The
...Download file "Micronutrien metabolism past and present (synthesis of vitamin A from beta carotene)" to see next pagesRead More
Cite this document "Micronutrien metabolism past and present (synthesis of vitamin A from beta carotene)"
(“Micronutrien metabolism past and present (synthesis of vitamin A from Essay”, n.d.)
Micronutrien metabolism past and present (synthesis of vitamin A from Essay. Retrieved from https://studentshare.org/miscellaneous/1503597-micronutrien-metabolism-past-and-present-synthesis-of-vitamin-a-from-beta-carotene
(Micronutrien Metabolism past and Present (synthesis of Vitamin A from Essay)
Micronutrien Metabolism past and Present (synthesis of Vitamin A from Essay. https://studentshare.org/miscellaneous/1503597-micronutrien-metabolism-past-and-present-synthesis-of-vitamin-a-from-beta-carotene.
“Micronutrien Metabolism past and Present (synthesis of Vitamin A from Essay”, n.d. https://studentshare.org/miscellaneous/1503597-micronutrien-metabolism-past-and-present-synthesis-of-vitamin-a-from-beta-carotene.
Cited: 0 times
CHECK THESE SAMPLES - THEY ALSO FIT YOUR TOPIC "Micronutrien metabolism past and present (synthesis of vitamin A from beta carotene)"
As many young people do, I took them for granted and did not really apply my best efforts to the subjects that I was studying. Perhaps some of my problem came from immaturity, but most of the problems in my education stemmed from the fact that I could not see any real connection between what I was studying and how it related to my future.
This paper discusses the differences between the past and modern age that have been caused by technology. Technological advancement has played a big role in eradicating slavery, facilitating communication, and making the journey time saving and convenient.
Therefore, this underlines the importance of the knowledge of nutritional value of foods that people consume and the right amount of the nutrients required in one serving or a day. Falling into two categories, in terms of solubility in either fat or water, vitamins are some of the nutrients important for the health of a human being.
While the three components may act independently from each one another, they are interrelated in various aspects, considering that it is the law enforcement component of the criminal justice system that supplies the other two components with the subjects to act upon, while the courts are responsible for controlling the other two components.
Money swings in the market, when financial crises arises in company, how financial needs are managed viz., in stock market most probably finance inflation may rise or fall and at the same time company's share market also fluctuates that may effect bank interest rate.
Arrangement for childcare services can be done in a child’s home or a structured childcare facility for preschool-age children. Children above 5 years may enjoy these services either through after school and before school programs. With
I believe that this course of substance abuse will help me to gain the required skills for guiding and counseling the people suffering from the drug abuse problems (University of the Pacific, 2014). I had chosen this particular course of substance abuse as I was highly
The author states that the ideas by Engels and Marx were quite influential in helping explain why people in crime are considered white collar are usually overlooked while the petty crimes are highly punishable by law. Taylor, Walton and Young combined Marxism and interactionalism to form part of the Neo-Marxist approach in criminology.
14 Pages(3500 words)Essay
GOT A TRICKY QUESTION? RECEIVE AN ANSWER FROM STUDENTS LIKE YOU!
Save Your Time for More Important Things
Let us write or edit the essay on your topic
"Micronutrien metabolism past and present (synthesis of vitamin A from beta carotene)"
with a personal 20% discount.