Browning thermostability

Some of the vanadium enzymes are thermostable (19), although not as much as enzymes in thermophilic bacteria (40). For example, the enzyme from the red seaweed C. rubrum (22) is less stable than that from the brown seaweed A. nodosum. This may be related to the habitat of the seaweeds, since red seaweeds remain submerged even at low tide. In contrast, A. nodosum, which is found near the high-tide level, is dry most of the time and in summer is exposed to considerable heat. Similarly, the enzyme fromX. parietina, a lichen that grows on sun-exposed stones, has been reported to be thermostable (23). 

Recently, comprehensive reviews have appeared on archaea in general by Brown et al. [1] and on the sulfothermophiles by Forterre[2] the latter review also includes an excellent discussion of general factors influencing thermostability at the DNA level. Moreover, many new isolates of hyperthermophiles have been characterized during the past decade and they have been described in two recent reviews by Stetter and colleagues [3,4] in Table 1 we present a recent view of the phylogeny of the hyperthermophiles taken from one of these [4]. The list of organisms is not complete since several isolates have recently been characterized which remain to be classified. 

A great number of patents deal with the derivative of antrachinone [100]. Thermostable and lightfast dye of green colour has been patented [101]. The firm CIBA suggests brown pigments thermostable in PA melt, in the molecule of which two substituted antrachinone residues are condensed by aromatic, more often polycyclic radical of naphthalene type, antrachinone and so on [102,103]. 

Pure 0. are nonreducing, r.s. 60-80, thermostable, meltable and there is no tendency for browning reactions. The competitive inhibition of glucan formation from sucrose in the oral region by Streptococcus mutans in the presence of o. is the reason for its application as a noncariogenic sweetener in Japan since 1980. 

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