Biology ETDs

Publication Date



The activity of extracellular coagulase, deoxyribonuclease, acid phosphatase, alkaline phosphatase and lipase for 10 strains of Staphylococcus aureus was investigated. The enzymatic activities were also tested for the presence of a specific enzyme inactivator. The relationship of EH and cell density to the five enzymes was also studied.

The extracellular enzymes used in these experiments were prepared by removing cells by centrifugation from the broth of O, 6, 12, 24, 36, 48, and 60 hr cultures. Cell numbers were determined by the standard plate count method. Inactivation of specific enzymes was measured by mixing equal volumes of 6 hr broth and 60 hr broth, and performing enzyme assays at the initial time of mixing (0 hr) and following 24 hr of incubation at 37 C.

There was some individual variation between strains in the amount of a particular enzyme produced, but generally there was observed an initial high activity of both coagulase and lipase enzymes at 6 hr incubation, followed by a sharp decline over the 60 hr test period. The opposite results were noted for alkaline and acid phosphatase. The activity gradually increased reaching a maximum at 60 hr of incubation. Deoxyribonuclease activity was high at 6 hr then decreased and gradually increased with time.

Several strains of Staphylococcus aureus showed inactivation of coagulase, acid phosphatase and lipase, however, there was no indication of inactivation of deoxyri­bonuclease or alkaline phosphatase.

The amount of inactivation of coagulase decreased after 24 hr of incubation at 37 C; one strain failed to show any inactivation at this time. Lipase inactivation increased with incubation while only one strain showed acid phosphatase inactivation after 24 hr incubation.

The results show a possible correlation between coagulase and lipase which may or may not be affected by deoxyribonuclease and the phosphatases. The role of an enzyme inactivator is proposed as a possibility for the results observed.



Document Type


Degree Name


Level of Degree


Department Name

UNM Biology Department

First Committee Member (Chair)

James S. Booth

Second Committee Member

John W. Beakley

Third Committee Member

Gordon V. Johnson

Included in

Biology Commons