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The Spike [or Victoria University College Review 1961]

Biochemistry at Victoria

page 30

Biochemistry at Victoria

The Biochemistry Laboratory was the first to start work in the Easterfield Building, in 1958, in somewhat improvised quarters on the fourth floor. The only hours available to the first Biochemistry II laboratory class were in the evening, and the only way to reach the laboratory was to wade through the mud of the quadrangle, and to climb the unlighted back stairs. It says much for the enthusiasm of the pioneer class of 1958 that rarely was any of them missing. Stage III started in 1959, and Masters in 1960; we hope to produce a Ph.D. by 1962. Unfortunately, because of our restricted accommodation, and of our even more restricted funds, we have had to restrict entry at all stages since the inauguration of this course.

It is natural that a country such as New Zealand, whose wealth depends so largely on animal and plant products, should be interested in biochemistry, which is basic to an understanding of the processes involved in all stages of primary production, storage, processing and transport of these products, and in the utilization of by-products. It is also natural that the Health services of New Zealand should be aware of the increasing importance of biochemistry for the understanding of the nature of disease, for its diagnosis, and for its treatment, as well as for its prevention. These considerations have evidently occurred to our students, who have included people working in hospital and other pathology laboratories, members of the Department of Scientific and Industrial Research, zoology and botany students, and straight chemists. It is conceivable that, with the passage of years, the realization of the importance of biochemistry to the well-being, both physical and economic, of the people of New Zealand might spread even further.

While it is most rewarding to help students to gain an understanding of the funda-mentals of biochemistry, and to teach them some of the techniques which have served for the elucidation of the data on which these are based, the whole process lacks vitality unless research work is being actively prosecuted, so that undergraduates can come into direct contact with post-graduate students, and can arrive at a realistic appreciation of both the thrills and the tedium and disappointment of research work. We are conducting a few lines of research, in a very modest way, commensurate with our facilities.

One of the most fascinating problems of biochemistry deals with the disposal of waste nitrogen, originating chiefly from the breakdown of protein, but partly from nucleic acids. Since each individual animal has its own distinctive proteins, food protein cannot be used directly, but must be broken down into its components, called amino acids, which the animal then reassembles into its own particular protein. Since the assortment of amino acids present in food protein is never (except perhaps in the case of cannibals) exactly the same as in the proteins of the given animal, an excess of food protein has to be eaten, so as to ensure that there is a sufficient supply of whichever amino acids are critically needed for the specific proteins of the animal. Hence many other amino acids will be present, but not needed, and these are converted into sugar or fat, while their nitrogen is split off as ammonia.

Ammonia is, however, very toxic, so that it must be got rid of by excretion into the page 31 medium in which the cells are immersed. This presents no appreciable hazards for aquatic forms of life, since the water in which they live dilutes the ammonia to supportable concentrations. Land animals cannot do this, and they are obliged to convert the ammonia into some non-toxic form. Various solutions of the problem are encountered in different life-forms, and the particular form in which excess nitrogen is eliminated appears to be related to the environmental conditions of the given life-form.

One of our students has been investigating the metabolism of uric acid in the housefly, in its various developmental stages. This was done by finding which organs contained the enzyme uricase, which catalyses the oxidation of uric acid, to yield a soluble product, called allantoin. The possession of this enzyme may be advantageous to animals, since they gain some energy from this oxidation, and at the same time escape the hazard of deposition of insoluble urates in various parts of the body. Some animals do not, however, possess uricase, such as birds, reptiles and most insects; in these animals there is an over-riding need to conserve water, and to restrict body-weight, and all their excess nitrogen is synthesized into uric acid, and eliminated in a semi-solid form. All mammals, except man and his cousins, the anthropoid apes, possess uricase; it might be supposed that the mutation which led to the development of the Hominids also involved the disappearance of the gene responsible for the production of uricase.

It has, indeed, been suggested that uric acid might have a stimulating effect on the central nervous system, similar to that of caffeine, and that the superior mental powers of the hominids are hence an indirect consequence of this mutation.

To revert to our houseflies, it was found that uricase was present in the eggs and maggots, but disappeared at pupation, was absent from the newly emerged adult, and then reappeared in the equivalent of the insect kidney, to reach a maximum content by the fourth day of adult life. The enzyme was found to differ in a number of respects from mammalian uricase, as well as to resemble it in many other ways.

We are also investigating the purification of ox-kidney uricase, with the hope eventually of obtaining it in the pure crystalline state.

Work is also in progress on the vitamin requirements of arthropods, with particular reference to their visual pigments. This research is still in its preliminary stages, but it promises to yield quite interesting results.

R. Truscoe