Hendrickson, of the Office of Naval 

 Research, he determined the three- 

 dimensional shape of hemerythrin, an 

 accomplishment which clarified the 

 role of iron in carrying oxygen. 

 Klippenstein then turned to another 

 metalloprotein, ribonucleotide reduc- 

 tase, an enzyme which exerts some 

 control over the synthesis of DNA 

 (deoxyribonucleic acid). If DNA pro- 

 duction could be inhibited, they rea- 

 soned, this might have application in 

 the treatment of cancer, a disease in 

 which cell growth is uncontrolled. 

 Klippenstein chose the calf thymus as 

 his source of the enzyme, but to study 

 it required purification — in this case 

 a long, tedious, complex process. 

 Klippenstein never completed this 

 work because in 1982 he died sud- 

 denly at the age of 41. But in the 

 previous year he and his associates 

 had published a paper entitled, "Puri- 

 fication of the two complimentary 

 subunits of ribonucleotide reductase 

 from calf thymus." 



The interest of another protein 

 chemist in the department, J. A. 

 Stewart, is focused on developmental 

 biology, the larger problem addressed 

 being the reduced brain function re- 

 sulting from dietary protein deficiency 

 of the pregnant mother on the number 

 of brain cells and brain weight of the 

 offspring at birth. The mouse is used 

 as the model. One finding was that 

 maternal restriction of protein in fe- 

 male mice prior to mating and during 

 pregnancy resulted in offspring at birth 

 with decreased brain weight and pro- 

 tein content. 



Stewart served as department 

 chairman from 1977 to 1986 when he 

 became Associate Dean for Research 

 and Agricultural Experiment Station. 



D. M. Green, a biochemical geneti- 

 cist and department chairman since 



1986, utilizes the soil bacterium Ba- 

 cillus subtilis as a tool in the technique 

 of genetic engineering. At a certain 

 stage in the cell cycle the bacterium 

 will accept new genes giving the genetic 

 engineer the opportunity to study gene 

 function, i.e., what controls gene ac- 

 tivity. Using modern techniques, he 

 developed a method for separating 

 proteins, mostly enzymes, in bacteria. 

 Green has studied two genes in Bacillus 

 subtilis which control some nine other 

 genes, to make several different pro- 

 teins involved in the exchange of ge- 

 netic material. The method, which 

 showed the complexity of nuclease 

 species not previously described in 

 this organism, gives excellent resolu- 

 tion. 



E. J. Herbst has studied polyamines, 

 specifically spermidine and spermine. 

 He was the first to show that production 

 of these compounds occurred at the 

 same time and rate as nucleic acids, 

 substances which along with proteins 

 are essential for rapid grov^. Stimu- 

 lated by the suggestion that extraordi- 

 nary amounts of polyamines are pro- 

 duced during growth of tumor, he 

 searched for compounds which would 

 inhibit production of polyamines. 

 Herbst then investigated the mechanism 

 by which one of these compounds, a- 

 difluoromethylornithine (DFMO), de- 

 presses cancer growth. Research else- 

 where has shown that DFMO prevents 

 the growth of the malaria parasite in 

 humans and coccidia in chickens. 



Both classical genetics and the 

 new recombinant DNA technology are 

 used by biochemical geneticist C. L. 

 Denis working with yeast to deter- 

 mine how enzymes are turned on and 

 off in both normal and abnormal phases 

 of growth and development — thus his 

 research has a tie to cancer. Some of 

 the enzymes activated during unregu- 



63 



