Date of Award


Document Type


Degree Name

Master of Science (MS)


Biomedical Sciences

First Advisor

John A. Duerre


Microorganisms, plants and the major organs from cold and warm blooded vertebrates ware assayed for the presence of S-adenosylhomocysteine hydrolase, S-adenosylhomocysteine nucleosidase, S-ribosylhomocysteine cleavage enzyme and homoserine dehydratase.

S-Adenosylhomocysteine hydrolase was found in all yeasts and plants assayed and in the livers of all cold blooded vertebrates assayed except the Polyodon spathula (Paddlafish). Liver extracts from all warm blooded vertebrates except the Odocoileus hemionus (Mule deer), Odocoileus virginianus (Whitetail deer) and Homo sapiens (human) were also found to possess S-adenosylhomocysteine hydrolase. This enzyme was also found in the spleens of the Ictalurus punctatus (Channel cat), Perca flavescens (Yellow perch) and Bos (steer) and in the kidneys of the Ictiobus bubalus (Buffalohead), Ictalurus punctatus (Channel cat), Thamnophis sirtalis (Garter snake), Anas platyrhynchos (Rouen duck), Totanus flavipes (Lesser Yellowleg), Rattus rattus (white rat), Oryctolagus cuniculus (New Zealand white rabbit) and Canis familiaris (dog). There was no hydrolase activity found in brains or hearts of any of the vertebrates assayed. S-Adenosylhomocysteine hydrolase was also lacking in all bacteria assayed.

S-Adenosylhonocysteiifie nucleosidase activity was not detectable in any yeasts, plants or vertebrate organs assayed. This enzyme was present in all bacteria assayed except Bacillus subtilis.

S-Ribosylhomocysteine cleavage enzyme was lacking in all extracts assayed except Citrobacter freundii, Enterobacter aerogenes, Escherichia coli and Proteus vulgaris.

Homoserine dehydratase was found in Bacillus subtilis, >u>Bacillus cereus, Sarcina lutea and in all liver extracts except those of Ictiobus bubalus (Buffalohead), Galus galus (White Leghorn chicken), Pedioecetes phasianellus (Sharptail grouse), Cavia porcellus (Guinea pig), Oryctolagus cuniculus (New Zealand white rabbit) and Canis familiaris (dog). This enzyme was also found in brain extract of the Anas platyrhynchos (Rouen duck) and kidney extracts of Totanus flavipes (Lesser Yellowleg), Rattus rattus (white rat) and Odocoileus virginianus (Whitetail deer). Homoserine dehydratase was lacking in Gram negative bacteria, yeasts, plants and from hearts and spleens of all vertebrates assayed.

Intravenous injections of S-adenosylhomocysteine into an anesthetized dog resulted in a rapid excretion of this compound in the urine with minimal retention by any organ assayed. As the liver and kidney had been found to contain S-adenosylhomoeysteine hydrolase these results suggested that this enzyme is inoperative against exogenous S-adenosylhomocysteine.