Showing papers by "Alexander N. Glazer published in 1971"

14 Papain and Other Plant Sulfhydryl Proteolytic Enzymes

Abstract: Publisher Summary Papain is a simple protein containing only amino acids and devoid of carbohydrate All of the usual amino acids are present with the exception of methionine Papain contains no chromophoric groups other than its constituent amino acids It is rich in tyrosine and tryptophan The amount of active enzyme in papain solutions can be determined by a number of methods Finkle and Smith showed that the sulfhydryl (SH) titer of papain was a direct measure of the amount of active enzyme present Papain is routinely assayed in the presence of freshly prepared 0005 M cysteine and 0001 M ethylenediaminetetraacetic acid (EDTA) The mechanism of action of papain, ficin, chymopapain, and bromelain is very similar While the sequences near the essential thiol groups in these enzymes display varying degrees of homology, judgment as to whether all of these enzymes arose from a common evolutionary precursor has to await more extensive information on their amino acid sequences These enzymes are all activated by SH compounds and cyanide and inactivated by mild oxidizing agents

Subunit Structure of the Phycobiliproteins of Blue-Green Algae

Abstract: The phycobiliproteins of the blue-green algae Synechococcus sp. and Aphanocapsu sp. were characterized with respect to homogeneity, isoelectric point, and subunit composition. Each of the biliproteins consisted of two different noncovalently associated subunits, with molecular weights of about 20,000 and 16,000 for phycocyanin, 17,500 and 15,500 for allophycocyanin, and 22,000 and 20,000 for phycoerythrin. Covalently bound chromophore was associated with each subunit.

Characterization of phycoerythrin from a Cryptomonas sp.

Abstract: Two closely similar phycoerythrins were purified from Cryptomonas sp. The two proteins were indistinguishable with respect to native molecular weight, subunit structure, photolability and immunological specificity, and differed only in their isoelectric points (pH 5.74 and 6.35), as determined by isoelectric focussing in polyacrylamide gels. Each protein consisted of two unequal subunits, α (mol. wt. 11,800) and β (mol. wt. 19,000), and each subunit contained covalently bound chromophore. In contrast to the blue-green and red algal phycoerythrins studied thus far, the Cryptomonas sp. phycoerythrins are extremely photolabile; exposure of the purified proteins to relatively short periods of intense illumination with visible light produces a marked decrease in fluorescence and in absorbance at 567 mμ.

Comparative immunology of algal biliproteins.

Abstract: The three spectroscopically distinct classes of phycobiliproteins characteristic of the Cyanophyta and Rhodophyta—phycocyanins, allophycocyanins, and phycoerythrins—share no common antigenic determinants detectable by the Ouchterlony double diffusion technique. Each class of phycobiliprotein, from both Cyanophyta and Rhodophyta, possesses a strong determinant common to all members of that class. With respect to an antiserum directed against a specific cyanophytan biliprotein, all heterologous biliproteins of the same class are immunologically identical, as shown by the fact that absorption with a given heterologous antigen simultaneously eliminates crossreactions with other heterologous antigens. A cryptophytan phycoerythrin was found to be immunologically unrelated to any of the cyanophytan or rhodophytan biliproteins examined.