# POST-RIBOSOMAL PROTEOGLYCAN MODIFICATION

> **NIH NIH R01** · UNIVERSITY OF MINNESOTA · 1993 · $126,654

## Abstract

Phosphorylation at the 2-position of xylose of chondroitin sulfate was
initially discovered in aggrecan from the Swarm rat chondrosarcoma.
Following this discovery, phosphorylation of other glycosaminoglycan
(GAG) chains including chondroitin sulfate, dermatan sulfate and heparan
sulfate were found.  The exact function of this modification still
remains unknown.  The role of phosphorylation in the intracellular
sorting and control of synthesis of proteoglycans (PGs) will be
investigated using tissue culture, radioisotopic labelling, and chemical
analysis.  The detailed structure of the glycosaminoglycan modification
of the linkage region in the Swarm rat chondrosarcoma chondroitin sulfate
PGs and the EHS heparan sulfate PGs will continue to be investigated.

We will develop an assay for xylose phosphorylating enzyme(s), purify it
and determine its chemical and physical properties, its donor and
substrate specificities and subcellular distribution.  We will determine
the structure of the initial modification, identify the phosphorylating
sites along the protein core, and obtain partial amino acid sequences for
such sites.

In developing the method for assaying the phosphorylating enzyme, we will
use a silk fibroin or small peptides as substrates and partially purified
xylosyl transferase from the Swarm rat chondrosarcoma or EHS sarcoma to
prepare potential substrates.  Additionally, a new mercurial method will
be used to remove nonreducing unsaturated glucuronic acid residue from
chondroitinase AC-treated PGs and enzymes will be used to degrade the
molecule into the linkage region.  This will provide high molecular
weight substrates that will then be used to probe subcellular
fractionations for the enzyme.  Structural techniques will be used to
define the properties of the phosphorylated products.  The degraded
linkage region preparation will be used to produce monoclonal antibodies
to the linkage region.  The results of the study will be used to propose
a role of phosphorylation in PG synthesis.

## Key facts

- **NIH application ID:** 3156281
- **Project number:** 5R01AR032372-10
- **Recipient organization:** UNIVERSITY OF MINNESOTA
- **SAM.gov UEI:** KABJZBBJ4B54
- **Principal Investigator:** Theodore Richard Oegema
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1993
- **Award amount:** $126,654
- **Award type:** 5
- **Project period:** 1983-07-01 → 1996-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3156281

## Citation

> US National Institutes of Health, RePORTER application 3156281, POST-RIBOSOMAL PROTEOGLYCAN MODIFICATION (5R01AR032372-10). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3156281. Licensed CC0.

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