Actinomycete metabolism: α-phenylmannosidase of Streptomyces griseus

Abstract

K was demonstrated that cultures of Streptomyces griseus possess an enzyme capable of liberating phenol from phenyl [alpha] -D-mannoside. The opt. pH for the activity of the enzyme is approx. 8.0. The enzyme is very sensitive to conditions of aeration. Decreased aeration causes a marked decrease of enzyme activity. Mannose, methyl [alpha]-D-mannoside, maltose and cellobiose strongly inhibit the enzyme. A number of other sugars have little or no effect. Ferrous and cupric ions have some inhibitory effect on the enzyme. K+, Ca2+, Mg2+ and Ba2+ have no effect. The rate of enzymic cleavage of substrate is not influenced by inorganic phosphate. Arsenate increases the rate. Cyanide and sulphite inhibit the enzyme, iodoacetate has no effect. The Michaelis constant of the enzyme with respect to phenyl [alpha] -D-mannoside is less than 10-4 [image]. It is probable that the same enzyme is responsible for the conversion of mannosido-streptomycin into streptomycin and the hydrolysis of phenyl [alpha] -D-mannoside.