L-gulonolactone oxidase

by Séverine Altairac

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We are all used to being served a glass of orange or grapefruit juice for breakfast. Not so long ago, there was only toast and a cup of tea. When did the orange juice come in? In 1747, a ship's astute doctor gave oranges to its sailors and, in time, noticed that those that had been suffering from scurvy got better. Today, we know that scurvy is caused by vitamin C insufficiency. The daily dose we require equals to two oranges. Why? Vitamin C takes part in a number of essential functions in our body such as the prevention of aging and the synthesis of collagen which, amongst other things, maintains tissue structure.

Topping up our diets with food items rich in vitamin C seems quite natural to us. However, most mammals make their own vitamin C. So why have humans lost the faculty to do so? It's all because of Gulo. Gulo is a protein which synthesizes vitamin C. About 40 million years ago, a mutation on the Gulo gene in humans turned out to be fatal and we haven't been able to produce any since. Gulo is also inactive in other species such as chimpanzees, Guinea pigs and a few bats who, like us, have to find their vitamin C in what they eat.

The metabolic process which results in vitamin C synthesis is complex. A number of bioinformatics tools - known as metabolic maps - are able to render a global and comprehensive visualization of the different stages of vitamin C production. Comparisons between species are then possible and can shed light on differences such as those which exist between mice and men for example.

Hence our incapacity to synthesize vitamin C is the doings of only one protein... Fascinating in a way, isn't it? And there are many more fascinating tales of the like which revolve around the planet of genes and proteins. Because of - or thanks to - them we are born either male or female. It is also thanks to our genes and proteins that we have the faculty to speak, that we know who our ancestors were and why we feel hungry or replete. And none of this could be at the stage it is now without the help of tools that have developed over the years at the same time as computers evolved - this is the world of bioinformatics.

On the occasion of the Swiss Institute of Bioinformatics' 10th anniversary, we conceived and created an exhibition 'Chromosome Walk, a saunter along the human genome'. It was an ideal opportunity to present the tiny world of genes and proteins, which makes us what we are. The exhibition leads you into the heart of a cell and its chromosomes. You are invited to take a walk along our genome and in so doing discover some of the mechanisms that lie beneath the making of Life.

An excerpt from our exhibition, which presents chromosome 8, "How about an orange?"
More on our exhibition here : Chromosome Walk, a saunter along the human genome

UniProt cross references
L-gulonolactone oxidase (Gulo), Mus musculus (Mouse): P58710
Protein Spotlight (ISSN 1424-4721) is a monthly review written by the Swiss-Prot team of the SIB Swiss Institute of Bioinformatics. Spotlight articles describe a specific protein or family of proteins on an informal tone. Follow us: Subscribe · Twitter · Facebook