Affinity sites for N-acetyl-beta-D-glucosaminidase on the surface of rat epididymal spermatozoa.

BARBIERI A; SOSA MA; COUSO R; IELPI L; MERELLO S; BARRERA P, JIMENEZ-ORTIZ V , SARTOR T, TONN C , GIORDANO O , GALANTI N , SOSA MA; BERTINI F

INTERNATIONAL JOURNAL OF ANDROLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 1994 vol. 17 p. 43 - 49

0105-6263

The binding of N-acetyl-beta-D-glucosaminidase from rat epididymal fluid to the surface ofspermatozoa from the cauda epididymis was measured in the presence of sugars, itsphosphorylated derivatives, or after treatment of the cells or the enzyme with agents that alterthe integrity of proteins or carbohydrates. The binding was saturable, with a Kd in thenanomolar range, was inhibited with phosphorylated derivates of fructose, and did not dependon Ca2+, showing that it is different from the mannose 6-P-recognizing system existing in othertissues for this and other acid hydrolases. Treatment of the cells with sodium periodate ortrypsin inhibited the binding, showing that a glycoprotein of the plasmalemma is involved in theaffinity site. Fructose or phosphorylated derivates were not detected in the proteins of theepididymal fluid with HPLC. However, with the method used, the presence of these compoundscannot be ruled out, if among the proteins of the fluid there are only a small number of acidhydrolases containing this sugar.