TY - JOUR
T1 - Purification of a high-affinity discoidin I-binding proteoglycan from axenic Dictyostelium discoideum growth medium
AU - Bartles, James R.
AU - Santoro, Barbara C.
AU - Frazier, William A.
PY - 1981/5/18
Y1 - 1981/5/18
N2 - The axenic Dictyostelium discoideum growth medium HL-5, prepared using Difco proteose peptone No. 2, contains an extremely potent inhibitor of the binding of 125I-labeled discoidin I to glutaraldehyde-fixed, cohesive D. discoideum cells. Axenic strain A3 D. discoideum cells bind or internalize the inhibitor during growth in HL-5 medium and subsequently shed or excrete it while differentiating in suspension. The inhibitor has been purified from Difco proteose peptone No. 2 by sequential gel filtration on Sepharose 4B and affinity adsorption using discoidin I-Sepharose. The inhibitor is heterogeneous in molecular weight (4 · 105-2 · 106), but is relatively homogeneous in density on CsCl density gradients. The size and activity of the inhibitor are resistant to periodate, reduction and maleylation, proteases, nucleases and heating in the absence or presence of sodium dodecyl sulfate. Mild alkali causes a partial reduction in activity and converts the higher molecular weight fraction of the inhibitor to a lower molecular weight. The purified inhibitor contains neutral hexose, hexosamine and amino acid in an approximate molar ratio of 4 : 3 : 2. These and other properties suggest that the inhibitor is an unusual proteoglycan. Certain well-characterized glycosaminoglycans are relatively potent inhibitors of discoidin I binding. The proteoglycan reported here is the most potent discoidin I-binding inhibitor ever identified.
AB - The axenic Dictyostelium discoideum growth medium HL-5, prepared using Difco proteose peptone No. 2, contains an extremely potent inhibitor of the binding of 125I-labeled discoidin I to glutaraldehyde-fixed, cohesive D. discoideum cells. Axenic strain A3 D. discoideum cells bind or internalize the inhibitor during growth in HL-5 medium and subsequently shed or excrete it while differentiating in suspension. The inhibitor has been purified from Difco proteose peptone No. 2 by sequential gel filtration on Sepharose 4B and affinity adsorption using discoidin I-Sepharose. The inhibitor is heterogeneous in molecular weight (4 · 105-2 · 106), but is relatively homogeneous in density on CsCl density gradients. The size and activity of the inhibitor are resistant to periodate, reduction and maleylation, proteases, nucleases and heating in the absence or presence of sodium dodecyl sulfate. Mild alkali causes a partial reduction in activity and converts the higher molecular weight fraction of the inhibitor to a lower molecular weight. The purified inhibitor contains neutral hexose, hexosamine and amino acid in an approximate molar ratio of 4 : 3 : 2. These and other properties suggest that the inhibitor is an unusual proteoglycan. Certain well-characterized glycosaminoglycans are relatively potent inhibitors of discoidin I binding. The proteoglycan reported here is the most potent discoidin I-binding inhibitor ever identified.
KW - (D. discoideum)
KW - Discoidin I binding
KW - Proteoglycan
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U2 - 10.1016/0304-4165(81)90367-6
DO - 10.1016/0304-4165(81)90367-6
M3 - Article
C2 - 7236735
AN - SCOPUS:0019883758
VL - 674
SP - 372
EP - 382
JO - Biochimica et Biophysica Acta - General Subjects
JF - Biochimica et Biophysica Acta - General Subjects
SN - 0304-4165
IS - 3
ER -