Laminarin, molecular weight

Another purified enzyme preparation which produces laminaripentaose from insoluble laminarin and from heat-treated pachyman is produced by a strain of Arthrobacter luteus (100,101,102) when grown on yeast cells or / -(1 —>3)-glucan. The enzyme, which was named Zymolase (also referred to as Zymolyase) appeared to be homogeneous by electrophoresis in a Tiselius apparatus and by ultracentrifugation. The molecular weight of the enzyme was estimated from ultracentrifugation to be ca. 20,500. The optimum pH for lysis of viable yeast cells was 7.5. The optimum temperature was 35°C. The optimum pH for heat-treated pachyman hydrolysis was 6.5, and the optimum temperature was 45°C. A Lineweaver-Burk plot with heat-treated pachyman yielded a Km value of 0.04% when the solubilized carbohydrate was assayed by the phenol-sulfuric acid method. Zymolase lost all its activity after incubation at 60°C for 5 min. 

The following study of laminarin polysaccharides illustrates the potential of MALDI-MS for rapidly and sensitively defining the degree of polymerization (d.p.) of carbohydrate polymers and for revealing structural modifications which result in altered molecular weight. 

Laminarins are a class of low-molecular-weight storage p-glucans of brown algae consisting of (l-3)-linked P-D-glucopyranose residues in which some 6-D-branching in the main chain and some p(l-6)-intrachain links are present. The majority of... 

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