Gunnar Lundblad

Proteolytic activity in sea urchin gametes

1. 1. A protease effect has been found in sperm extracts from the sea urchin species Arbacia lixula, Paracentrotus lividus and Psammechinus miliaris. 2. 2. Proteolytic activity is found in extracts from lyophilized eggs of Arbacia and Paracentrotus. Some minutes after fertilization there is a strong increase in activity, followed by a decrease, so that after half an hour the activity is of the magnitude of that in unfertilized eggs or less. 3. 3. Seven hours after fertilization proteolytic activity again appears. 4. 4. Solutions of jelly coats from unfertilized eggs also have a proteolytic effect, tested on gelatin as well as haemoglobin.

β-N-acetylglucosaminidase from Entamoeba histolytica

Abstract 1. 1. In vitro cultures of Entamoeba histolytica strains HK-9 and NIH-200 contained considerable amounts of the acid hydrolase β - N -acetylglucosaminidase. The results indicate that this enzyme is produced by the amoebae and secreted into the growth medium. 2. 2. The enzyme was purified 1000–2000 fold and preliminarily characterized. In cultures from NIH-200 two β - N -acetylglucosaminidases with distinct pls, pH optima and kinetics were demonstrated. From cultures of HK-9 only one enzyme was isolated and it seems that it was identical with one of the NIH-200 enzymes. The molecular weight of all three enzymes was 125,000 ± 10,000. 3. 3. As it is known that hydrolases can be involved in inflammatory conditions it is suggested that released β - N -acetylglucosaminidases participate in the pathogenesis of amoebiasis.

Glycosidases in lymphomyeloid (hematopoietic) tissues of elasmobranch fish

Abstract 1. 1. High lysozyme and chitinase activities were found in Leydigs organ of Etmopterus spinax, Somniosus microcephalus and Torpedo nobiliana, in Leydigs and epigonal organs and spleen of Raja radiata, and in the epigonal organ of Rhinoptera bonasus. 2. 2. Strong chitinase activity with little or no lysozyme activity was noted in Leydigs and epigonal organs of Scyliorhinus canicula, and in the epigonal organ of Ginglymostoma cirratum and Heterodontus francisci. 3. 3. Very high β-N-acetylglucosaminidase activity was found in lymphomyeloid organs of all species investigated, and in the pancreas of Somniosus microcephalus. 4. 4. Thirteen other glycosidases were assayed in lymphomyeloid and digestive tissues of Ginglymostoma cirratum, Heterodontus francisci and Etmopterus spinax. Activities of α- d -mannosidase, β- d -galactosidase, β- d -N- acetylgalactosaminidase , β- d -glucuronidase and α- and β- d -glucosidase usually were higher in lymphomyeloid tissues than in digestive tissues.

Chitinase and beta-N-Acetylglucosaminidase in the Digestive Juice of Helix pomatia.

A beta-N-acetylglucosaminidase from Helix pomatia digestive juice was separated and partly purified by gel chromatography. The optimal pH for the degradation of p-nitrophenyl-N-acetyl-beta-D-glucosaminide was 3.4. The molecular weight was around 160 000 and the pI = 4.95. In the same gel chromatography run two chitinase active peaks were also obtained. These chitinase active peaks were also obtained. These chitinases, with molecular weights around 26 000 and 13 000, had somewhat different pH activity curves with optima at 4.2 and 4.3. By isoelectric focusing the first peak with molecular weight around 26 000 was divided in two chitinase active regions with pI at 5.7 and 3.5. The second peak with molecular weight around 13 000 had a pI at 7.3.

Degradation of starch, hydroxiethyl cellulose ether and chitosan by enzymes in spermatozoa and sperm fluid from Psammechinus and Modiola☆☆☆

Abstract The semen of Psammechinus and Modiola contains cellulase, and has also the ability of depolymerizing chitosane. The semen of Psammechinus also contains amylase, whereas Modiola was not tested in this respect. The enzymes are present both in the spermatozoa and in the suspending medium. The optimum pH for activity is for amylase about 7 and for cellulase about 6.

β-N-Acetylhexosaminidase and α-d-mannosidase from the epigonal lymphomyeloid organ of the nurse shark (Ginglymostoma cirratum)

1. 1. Lymphomyeloid (lymphohaemopoietic) tissues are rich in glycosidases probably contained within leucocytes. The glycosidases β-N-acetylhexosaminidase and α-d-mannosidase found in the epigonal organ—a prominent lymphomyeloid tissue of the nurse shark Ginglymostoma cirratum—were purified and preliminary characterized. 2. 2. The enzyme β-N-acetylhexosaminidase was assayed as N-acetyl-β-d-glucosaminidase but was shown to have also N-acetyl-β-d-galactosaminidase activity. The pH optima were 4.5 and 4.2 for these two substrates. The enzyme was purified 40-fold by gel filtration. By isoelectric focusing the enzyme showed multiple forms with pIs = 6.0, 6.5, 6.7 and 6.9. The molecular weight was 144,000 ± 13,000 (SD) estimated by gel filtration. 3. 3. α-d-mannosidase was purified 30-fold by gel filtration. Isoelectric focusing in a narrow pH range gave the pI values 7.3, 7.6 and 7.85. The main pH optima were at 3.3, 3.7 and 4.5. The molecular weight was 275,000 ± 19,000 (SD).