Structural and Regulative Genes Controlling Tyrosinase Synthesis in Neurospora

Horowitz, N. H.; Fling, Marguerite; Macleod, Helen; Watanabe, Y.

doi:10.1101/sqb.1961.026.01.028

Cited by 61 publications

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“…Enzymatic activity first appeared between 4.5 to 8.5 h following the addition of ethionine. This is in agreement with previous reports [1,6,21]. Tyrosinase activity increased for about 65 h and then declined, while control cultures showed only low levels of activity.…”

Section: Immunochemical Studies On Tyrosinase Inductionsupporting

confidence: 83%

Immunochemical Studies on Tyrosinase Induction in Neurospora

Katan

Galun

Arnon

1975

European Journal of Biochemistry

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An immunoassay for tyrosinase, using the modified bacteriophage technique, was developed : Tyrosinase of Neurospora was conjugated to bacteriophage T4 using glutaraldehyde as a cross-linking agent. The conjugated phage that survived the coupling process could be inactivated by antiserum raised in rabbits against pure tyrosinase, but not by normal serum. This inactivation was specifically inhibited by pure Neurospora tyrosinase, and the degree of inhibition was proportional to the concentration of tyrosinase within the range of 30-150 ng/ml. Crude mycelial extracts possessing tyrosinase activity could similarly inhibit the inactivation of the conjugated phage by the antiserum. To evaluate the tyrosinase content of crude extracts, their inhibitory capacity was compared to that of known amounts of pure tyrosinase, and the amounts thus calculated agreed with those predicted from an enzymatic assay.The tyrosinase-bacteriophage immunoassay was used for the quantitation of tyrosinase-antigen in crude extracts of Neurospora cultures that had been induced to form tyrosinase by the addition of ethionine. Enzymatic activity appeared after a lag of several hours, increased for 2-3 days and then declined. Immunological assays of these cultures showed : (a) serologically reactive protein started to accumulate upon culture starvation and was evident during the lag period; (b) specific activity (units per mg antigen) was constant throughout induction; (c) at the phase of decrease in mycelial enzyme content, increasing amounts of serologically reactive protein were detected in the medium, indicating that some enzyme was eventually excreted. These results show that the lag is not a qualitatively distinct period, and support the previously forwarded notion that tyrosinase is synthesized de novo upon induction

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Section: Immunochemical Studies On Tyrosinase Inductionsupporting

confidence: 83%

Immunochemical Studies on Tyrosinase Induction in Neurospora

Katan

Galun

Arnon

1975

European Journal of Biochemistry

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“…This study of the induction of laccase synthesis in Neurospora permits a comparison with the mechanisms regulating this enzyme in other fungi (3,4,7,18) and also with the regulatory systems for tyrosinase and ' Present address: Department of Neurobiology, Harvard Medical School, Boston, Mass. 02115 related enzymes in Neurospora (10,11,12,13,14,15).…”

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confidence: 99%

Induction of Neurospora crassa Laccase with Protein Synthesis Inhibitors

Froehner

Eriksson

1974

J Bacteriol

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Rapidly growing Neurospora crassa does not produce laccase ( p -diphenol:oxygen oxidoreductase; EC 1.10.3.2). Low concentrations of cycloheximide induce the production of this enzyme, most of which is secreted into the media. In general, limited inhibition of protein synthesis seems to derepress laccase synthesis since actinomycin D and, to a limited extent, puromycin also induce laccase production. Similarities in the conditions of laccase and tyrosinase induction, plus investigations with two tyrosinase regulatory mutants, suggest that the production of these two phenol oxidases is controlled by the same mechanism. As shown by polyacrylamide gel electrophoresis, most of the 10 to 12 proteins normally present in the medium virtually disappear during cycloheximide treatment. In contrast, the amounts of two proteins that are present in only very minor quantities, if at all, in normal culture filtrates increase dramatically. One of these proteins co-migrates with laccase, whereas the other has not been identified.

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“…They also found that the mushroom isozymes 446 Multiple Forms of Phenoloxidase were to a certain degree interconvertible, depending on pH, ionic strength, and protein concentration. Horowitz and Fling (1953) showed the presence of several forms of tyrosinase in Neztrospora crassa distinguished on the basis of their heat resistance, and later were shown to differ in their electrophoretic properties (Horowitz et al, 1961). Sussman (1961) found that a thermostable and a thermolabile form of tyrosinase existed.…”

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confidence: 99%

Multiple Forms of Phenoloxidase

Constantinides

Bedford

1967

Journal of Food Science

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SUMMARY— The phenoloxidase system in the tissues of mushrooms, potatoes, and apples was investigated using a polyacrylamide electrophoretic technique. The enzyme system was shown to exhibit the phenomenon of multiple forms. The multiple form pattern obtained was highly characteristic for each individual species and variety studied, and substrate specificity was evident. The mushroom phenoloxidase system (Agaricus campestris) was shown to consist of at least nine distinct dl‐dopa‐reactive multiple forms, and at least three forms reacting with I‐tyrosine. Potatoes (var. Rural Russet) showed at least 11 bands of dl‐dopa activity, while apples (var. Golden Delicious) had at least three multiple forms of dl‐dopa activity. By introducing the “multiphase” gel electrophoretic technique a better resolution of the multiple forms was obtained. A group of closely related dl‐dopa multiple forms in mushrooms had the unique ability to withstand the temperature of 70°C for one hour. Sulfite, ethylenediamine‐tetraacetic acid (EDTA) and other treatments affected the multiple forms differently. Each multiple form behaved as an individual entity upon repeated elutions and electrophoreses.

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Structural and Regulative Genes Controlling Tyrosinase Synthesis in Neurospora

Cited by 61 publications

References 0 publications

Immunochemical Studies on Tyrosinase Induction in Neurospora

Immunochemical Studies on Tyrosinase Induction in Neurospora

Induction of Neurospora crassa Laccase with Protein Synthesis Inhibitors

Multiple Forms of Phenoloxidase

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