It has recently been ascertained that the coloration of certain sponges is due to the interaction of an oxydizing ferment, tyrosinase, upon certain colourless chromogenic substances.
Furth and Hugo Schneider showed that a tyrosinase could be obtained from the blood of certain insects, and, acting upon a chromogen present in the blood, converted it into a pigmentary substance of melanin-like nature.
Hans Przibram also extracted a tyrosinase ' from the ink-sac of Sepia, and, causing it to act upon a watery solution of tyrosin, obtained a black pigment.
von Ducceshi has also obtained a tyrosinase.
Bertrand have shown that certain fungi, the tissues of which, when exposed, to the air by injury, become immediately coloured, do so owing to the action of tyrosinase upon one or more chromogenous substances present in the plant.
Whether albinoes carry the tyrosinase or other ferment, or whether they carry the chromogen or chromogens, is not yet settled.
tyrosinase gene have been found to have developmental eye defects similar to those seen in human patients.
Biologically, melanin production is controlled by the action of the enzyme tyrosinase.
Obviously, we may regard C as a tyrosinase and R as a chromogen, or vice versa; and in the case of the white sweetpea crossed with a blue-flowered one, and producing purple offspring, we may imagine that the white flower brought in an additional tyrosinase or a chromogen not present in the blue flower, which, when combined or mixed with the chromogen or tyrosinase for blue, gave purple.
Mice missing the tyrosinase gene have been found to have developmental eye defects similar to those seen in human patients.
The tyrosinase test is more precise than the hair-bulb pigmentation test.
The hair converts tyrosine with the help of an enzyme called tyrosinase.
In some types of albinism, a genetic defect in tyrosinase means that the amino acid tyrosine cannot be converted by tyrosinase into melanin.
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