# LYSOSOMAL PROTEASES OF SPERMATOZOA

> **NIH NIH R01** · MEDICAL UNIVERSITY OF SOUTH CAROLINA · 1993 · $108,167

## Abstract

The long term objectives of this application are intended to establish the
biochemical properties and functional significance of new lysosomal-type
protease (endopeptidases and exopeptidases) recently detected in guinea pig
epididymal spermatozoa. One of the endopeptidases resembles lysosomal
cathepsin L, but is totally masked in epididymal sperm. A second cysteine
proteinase (which may be responsible for unmasking "cathepsin L") has also
been detected. This endopeptidase shares some properties with cathepsin S
-- a poorly studied lysosomal cysteine proteinase thus far found only in
lymphatic tissues. These two cathepsins are uniquely and selectively
concentrated (to the exclusion of detectable levels of cathepsins B and H)
in guinea pig sperm. The principal exopeptidase to be investigated
resembles dipeptidyl peptidase II (DPP II), a lysosomal enzyme belonging to
the serine catalytic class that is present at extraordinary levels in
epididymal sperm. Efforts will be made to purify these proteases from
freshly collected (guinea pig) epididymal sperm homogenates for the purpose
of establishing their molecular properties, substrate specificity, reaction
kinetics, inhibitor sensitivities, and immunological cross reactivity with
their lysosomal counterparts. Purification methods will be employed that
exploit differential solubilities, molecular size, charge, isoelectric
points, hydrophobicity, and special affinities. In view of the limited
supply of tissue available for this purification work, high performance
adaptations of traditional methodologies will be utilized. These (FPLC)
procedures, which are currently being employed in this laboratory, include
ion (anion and cation) exchange chromatography, molecular exclusion
chromatography, chromatofocusing, and hydrophobic interaction
chromatography. Specific fluorometric assays together with azo-dye and
fluorescence enzyme histochemical procedures will be employed (or
developed) as needed to assay and to localize these "new proteases" during
spermatogenesis and sexual development. The possible functional significant
of latent cathespin L will be assessed in relation to capacitation, the
acrosome reaction, and proacrosin activation. Insights gained from the
proposed studies will contribute to a basic understanding of the role of
acrosomal proteases in reproduction and facilitate a more rational approach
to problems of contraception, unexplained, infertility, and in vitro
fertilization.

## Key facts

- **NIH application ID:** 2199292
- **Project number:** 5R01HD024701-05
- **Recipient organization:** MEDICAL UNIVERSITY OF SOUTH CAROLINA
- **SAM.gov UEI:** NHV3GTWSALA7
- **Principal Investigator:** JOHN K MC DONALD
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1993
- **Award amount:** $108,167
- **Award type:** 5
- **Project period:** 1989-09-30 → 1995-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/2199292

## Citation

> US National Institutes of Health, RePORTER application 2199292, LYSOSOMAL PROTEASES OF SPERMATOZOA (5R01HD024701-05). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/2199292. Licensed CC0.

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