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Physical properties of β‐N‐acetyl‐D‐glucosaminidase and β‐N‐acetyl‐D‐hexosaminidase from Drosophila K c ‐cells
Author(s) -
Sommer Ulrich,
Spindler KlausDieter
Publication year - 1991
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/arch.940180105
Subject(s) - biology , hexosaminidase , drosophila (subgenus) , biochemistry , microbiology and biotechnology , enzyme , stereochemistry , gene , chemistry
K c ‐cells from Drosophila produce two different β‐D‐hexosaminidases, a β‐N‐acetyl‐D‐glucosaminidase (E.C.3.2.1.30) and a β‐N‐acetyl‐D‐hexosaminidase (E.C.3.2.1.52), which are also secreted into the medium. The M r of both enzymes is about 126,000 ± 9,700; the S‐values are 8.37 ± 0.44. Both enzymes have about the same pH optima at 5.5 and the same thermal stability. The temperature optima are identical (50°C) for both enzymes if p ‐nitrophenyl‐N‐acetylglucosaminide is used as a substrate. However, when p ‐nitrophenyl‐N‐acetylgalactoseaminide is used as the substrate the β‐N‐acetyl‐D‐hexosaminidase has a temperature optimum about 10°C higher. With higher salt concentrations, the activity of the β‐N‐acetyl‐D‐glucosaminidase increases, whereas β‐N‐acetyl‐D‐hexosaminidase is inhibited. Both enzymes also differ in their sensitivity to urea, the β‐N‐acetyl‐D‐hexosaminidase being less sensitive than the β‐N‐acetyl‐D‐glucosaminidase.