Jerome F. Fredrick

Glucosyltransferase isozymes in algae

Abstract Purified phosphorylase preparations from representative members of three algal Groups were subjected to two-dimensional electrophoresis on polyacrylamide gel. Three groups of closely associated isozymes were found in each preparation. Two isozymes of the conventional phosphorylase type were present in preparations from blue-green and from green algae; only a single enzyme appeared in red algal preparations. Two isozymes of the glucosyltransferase type, utilizing either UDPG or ADPG as substrate, were present in all three groups of algae. Each preparation examined by this orthacryl gel technique also showed the presence of two or three isozymes capable of “branching” linear polyglucosides.

The effect of 3-amino-1,2,4-triazole on phosphorylase of Oscillatoria princeps.

Abstract 1. 1. The inhibitory effect of 3-AT on Oscillatoria princeps phosphorylase is probably due to the chelation by 3-AT of the essential metal required by this enzyme. 2. 2. The inhibition of this phosphorylase by 3-AT can be effectively reversed by the addition of manganous or ferric ions only in the proper concentrations for forming the bivalent and trivalent chelates. 3. 3. Evidence is presented for the 3:1 structure of the ferric chelate of 3-AT.

Glucosyltransferase isozymes in algae—II. : Properties of branching enzymes☆

Abstract The branching isozymes of a Cyanophyte, Oscillatoria princeps , a Rhodophyte, Rhodymenia pertusa and a Chlorophyte, Spirogyra setiformis , when isolated by two-dimensional polyacrylamide gel electrophoresis, show an evolutionary progression. The isozymes were tested with various polyglucan substrates. Those of Oscillatoria were able to branch amylopectin and amylose, forming a phytoglycogenlike polymer which exhibited maximum absorption of its iodine complex at 550 nm. One of the three isozymes of Rhodymenia synthesized the identical polysaccharide, but the other two isozymes of this alga were without effect on amylopectin. They did branch amylose, however, forming a polyglucan which showed an absorption peak of its iodine complex at 580 nm. The green alga, Spirogyra , had three isozymes which were without effect on amylopectin, but which did branch amylose. The branched sugar formed by these algal enzymes showed an absorption peak of the iodine complex at 580 nm.

The structure of the d-glucose adduct of 3-amino-1,2,4-triazole: Infrared absorption studies

Abstract Chemical tests and infrared absorption spectra indicate that the d -glucose adduct of 3-amino-1,2,4-triazole is a definite chemical compound, an amine glucoside or secondary amine. The participation of this amine glucoside in phosphorylating reactions is discussed with respect to the observed effects on carbohydrate-metabolizing enzymes such as hexokinase and phosphorylase.

The α-1,4-glucans of Prochloron, a prokaryotic green marine alga

Abstract Prochloron , a symbiont found associated with Lissoclinum patella (a marine colonial ascidian), was lyophilized and its glucans extracted. The glucans were complexed with s -triazine reactive dyes and separated by electrophoresis on cellulose acetate membranes. A highly branched glucan similar to phytoglycogen, and a linear unbranched glucan resembling a short-chain amylose were both detected. This unusual polysaccharide mixture suggests a possible mode of starch biosynthesis in algae in general.

Storage glucan and glucosyltransferase isozymes of cyanidioschyzon merolae: A primitive eukaryote

Abstract Cyanidioschyzon merolae , a primitive eukaryotic alga isolated from supposedly pure cultures of the thermoacidophilic alga, Cyanidium caldarium , has many of the characteristics of such prokaryotes as bacteria and the cyanobacteria. Cyanidioschyzon appears to have even more of these prokaryotic features than does Cyanidium . Cyanidioschyzon divides by binary fission as do most bacteria. Its thylakoids are arranged along the periphery of the cell, like the cyanobacteria. Its formation of storage glucan, as well as the type of sugar formed is more like that of the blue-green algae rather than that of the red algae. Cyanidioschyzon merolae may be much more primitive than Cyanidium caldarium , and could be the most primitive eukaryotic cell.

Glucan and glucosyltransferase isozymes of Glaucocystis nostochinearum

Abstract The storage glucan of the alga, Glaucocystis nostochinearum was isolated in dimethyl sulfoxide. The absorption spectrum of its iodine complex was identical with those of other green algae but differed from that of blue-green algae. It was similar to amylopectin, and was much less branched than the phytoglycogen of Cyanophytes. The pattern of glycosyltransferase isozymes involved in the synthesis of this glucan (phosphorylases, synthetases and branching isozymes) was similar to those of Chlorophytes. The branching isozymes of this alga were typical Chlorophycean “Q” enzymes and could only insert branch linkages into linear amylose-like substrates; they were unable to further branch amylopectins, as can the branching isozymes of blue-green algae. If the plastids of this alga are endosymbiotic blue-green algae, then they have lost the ability to form highly branched glucans typical of Cyanophytes.

Further studies of primer-independent phosphorylase isozymes in the algae

Abstract Both Oscillatoria princeps and Cyanidium caldarium contain phosphorylase isozymes that can cause the synthesis of polyglucan from glucose-1-phosphate in the absence of added maltodextrin ‘primer’. In addition, O. princeps contains a primer-dependent phosphorylase isozyme. When the phosphorylase fractions isolated from extracts of the algae were treated with α-amylase, the primer-independent isozyme became primer-dependent and shifted from the position it was normally found at after polyacrylamide gel electrophoresis. This primer-independent isozyme became less mobile towards the anode, and was found at the locus usually occupied by the primer-dependent isozyme. It was not possible to restore its mobility towards the anode and its primer-independent properties by preincubation with maltoheptaose. The indication is that this isozyme is a glucoprotein and that the glucan component is chemically bonded to the protein.

Intraspecies evolution of enzymic mechanisms associated with the synthesis of α-1,4 storage glucans in two thermophilic-acidophilic algae of Cyanidium type

Abstract Cyanidium caldarium is an enigmatic eukaryotic alga which is both acidophilic and thermophilic. Its taxonomic position has been in doubt and, hence

Glucosyltransferase isozymes forming storage glucan in prochloron, a prokaryotic green alga

Abstract Since the prokaryotic, green marine alga Prochloron has not, as yet, been cultured, lyophilized cells were used in a microadaptation of polyacrylamide gel electrophoresis (PAGE) in order to isolate the glucosyltransferase isozymes. The pattern obtained with these capillary gels was identical with those of cyanophytes. Besides two phosphorylase and synthase isozymes, three branching isozymes of the b.e. type were found to be present.