UK Nobel surprize

(Photograph) - A BRITISH scientist is the joint winner of the Nobel Prize for Chemistry. This is the second year in which Britain has won it.

John Walker, aged 56, pictured above, a senior scientist at the Medical Research Council Laboratory of Molecular Biology in Cambridge, won half of this year's award jointly with Paul Boyer of the University of California Los Angeles for their explanation of how an enzyme forms adenosine triphosphate (ATP) - the carrier of energy in all living organisms from bacteria and fungi to plants and animals.

Dr Walker, the sixth Nobel laureate from the Cambridge laboratory, said the prize had come as a surprise. "I am overjoyed to have received this kind of recognition for myself, my colleagues and the laboratory," he said.

The Royal Swedish Academy of Sciences, which awards the 7.5 million krona ($1 million) prize, took the unusual step of dividing this year's award, with the other half going to Jens Skou of Aarhus University in Denmark, also for "pioneering work" on enzymes involved in the conversion of ATP.

Dr Walker and Professor Boyer receive their half of the award for their work on how the enzyme ATP synthase catalyses the formation of ATP.

Professor Boyer proposed a mechanism for how ATP is formed from adenosine diphosphate (ADP) and inorganic phosphate.

Dr Walker, who made his first studies of ATP synthase at the beginning of the 1980s, established the structure of the enzyme and verified the mechanism proposed by Professor Boyer. Dr Walker's starting point was that a detailed chemical and structural knowledge of the enzyme was required to understand how it functions.

He therefore determined the amino acid sequences in the constituent protein units. During the 1990s he collaborated with crystollographers to clarify the three-dimensional structure of ATP synthase. So far, the structure of part of the enzyme, the bulbous protruding F1 part, has been established.

Dr Walker said the prize came after 20 years of work. "My work is still ongoing. There is still plenty to do. We only know the atomic structure of half of it. We are working on the rest."