Search results for "Astacus leptodactylus"

Tyrosinases from crustaceans form hexamers

2002

Tyrosinases, which are widely distributed among animals, plants and fungi, are involved in many biologically essential functions, including pigmentation, sclerotization, primary immune response and host defence. In the present study, we present a structural and physicochemical characterization of two new tyrosinases from the crustaceans Palinurus elephas (European spiny lobster) and Astacus leptodactylus (freshwater crayfish). In vivo, the purified crustacean tyrosinases occur as hexamers composed of one subunit type with a molecular mass of approx. 71kDa. The tyrosinase hexamers appear to be similar to the haemocyanins, based on electron microscopy. Thus a careful purification protocol was…

Temperature adaptation influences the aggregation state of hemocyanin from Astacus leptodactylus.

2000

When Astacus leptodactylus were kept at various temperatures for several weeks, different ratios between di-hexameric and hexameric hemocyanins were observed in their hemolymph. The higher the temperature the more hexamers were present. This long-term adaptation to different temperatures or/and to temperature-induced pH-shifts as observed in the hemolymph has different effects on the expression of subunit types building up hexamers and those which covalently link two hexamers within the di-hexamers. The oxygen binding behaviour of di-hexameric hemocyanins from cold and warm adapted animals do not show differences with respect to affinity, Bohr effect and cooperativity.

Elimination and distribution of different substituted phenols by frog (Rana temporaria) and crayfish (Astacus leptodactylus)

1981

Differential regulation of hexameric and dodecameric hemocyanin from A. leptodactylus

2013

The oxygen binding properties of hemocyanins are regulated on a short time scale by effectors such as l-lactate, urate and protons, and on longer time scales by expression of the different types of subunits. For Astacus leptodactylus it was shown previously that acclimation to higher temperatures leads to increased levels of a 6-meric hemocyanin species, whereas at lower temperatures the 12-meric form prevails. Here we show that the temperature dependence of the two forms supports the idea, that the maintenance of high affinity towards oxygen is the driving force for the differential expression of these hemocyanins. Furthermore, the two different types of hemocyanin differ not only in the a…