# LEISHMANIA DONOVANI SURFACE MEMBRANES: 3 NUCLEOTIDASE

> **NIH NIH R01** · JOHNS HOPKINS UNIVERSITY · 1988 · $167,520

## Abstract

Initial studies of the enzymatic composition of the surface
membranes of the human pathogen Leishmania donovani and other
trypanosomatids have identified a very active 3'-nucleotidase.
Further studies of this enzyme have revealed several significant
characteristics:  1) This ectoenzyme has a dual function as both
a nucleotidase and nuclease which makes it ideally suited for
initiating purine salvage from exogenous nucleic acids, in these
organisms which lack the ability to synthesize the purine ring de
novo.  2) The enzyme activity in L. donovani and in the insect
trypanosomatid Crithidia luciliae is regulated by the supply of
available purines in culture media, i.e. purine-starved parasites
exhibit much higher levels of enzyme activity than do cells growing
in complete medium.  3) The enzyme activity may be renatured
following electrophoresis in SDS-polyacrylamide gels and
catalytically active polypeptides can be identified.  These
features warrant further investigation.

The studies proposed are intended to further the kinetic
characterization of the phosphomonoesterase and phosphodiesterase
activities of the 3'-nucleotidase/nuclease from L. donovani and
from purine-starved C. luciliae.  The enzyme will also be
characterized with respect to its physicochemical properties.
Another major goal of this proposal is to understand the mechanism
of regulation of the 3'-nucleotidase/ nuclease, especially the
regulated increase in the levels of enzyme activity when the
protozoa are starved for purines.

Our investigation of this trypanosomatid enzyme and its regulation
will require the purification of the enzyme and development of
specific antibody reagents.  Recombinant DNA techniques, especially
cDNA cloning of the gene, will be employed in order to address the
issues indicated above.

Results of such studies will provide new information on the
uniqueness of this enzyme and its role in parasite survival.
Studies of the enzyme's regulation will enable us to comprehend
differential enzyme, and gene, expression in these parasites.

## Key facts

- **NIH application ID:** 3126689
- **Project number:** 2R01AI016530-07A2
- **Recipient organization:** JOHNS HOPKINS UNIVERSITY
- **SAM.gov UEI:** FTMTDMBR29C7
- **Principal Investigator:** Michael Gottlieb
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1988
- **Award amount:** $167,520
- **Award type:** 2
- **Project period:** 1980-02-01 → 1990-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3126689

## Citation

> US National Institutes of Health, RePORTER application 3126689, LEISHMANIA DONOVANI SURFACE MEMBRANES: 3 NUCLEOTIDASE (2R01AI016530-07A2). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3126689. Licensed CC0.

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