Sweet potato origin

The purple add phosphatases of plant origin, in contrast, comprise a more heterogeneous class of enzymes A phosphatase from sweet potato, originally thought to depend upon Mn(III) for activity has recently been shown to consist of two apparently identical 53 kDa subunits, the holoenzyme bearing two atoms of iron However, discordance in the metal content may reflect differences in the spedes of sweet potato used in the isolation procedure, the Mn(in) protein being isolated from Japanese Kin-toki and the two-iron phosphatase from local American tubers In either case, at least one of these metal atoms is likely to be coordinated to tyrosyl residue(s) to account for the intense violet color and resonance Raman spectrum of the protein No direct evidence that the iron atoms in the two-iron protein are magnetically coupled is yet available, but spectroscopic similarities between the sweet potato and animal enzymes make this a reasonable conjecture. 

The International Potato Center, known worldwide by its Spanish acronym CAP, sees the potato and other Andean root and tuber crops as underexploited resources for agricultural development and hunger relief in developing countries. Founded in 1971, CIP has worked to enhance the cultivation, yield, processing, and consumption of potatoes. Its original mandate was expanded to include sweet potatoes and, more recently, other Andean roots and tubers in danger of extinction. 

In 1998, PDP collected samples of apple juice, cantaloupe, grape juice, green beans, orange juice, pears, spinach, strawberries, sweet potatoes, tomatoes, winter squash, com symp, milk, and soybeans. A total of 8500 samples were collected. Most of these were from fmits and vegetables (7017) with lower numbers of samples collected for whole milk (595), soybeans (590) and com symp (298). The majority of samples (84 percent) was of domestic origin. Overall, 45 percent of the samples contained no detectable residue while 26 percent contained one residue and 29 percent contained more than one residue. Residues exceeding the tolerance level were detected on 0.15 percent of the samples. In another 3.7 percent of the samples, residues of pesticides were detected on commodities for which no tolerances of the pesticides were established (USDA, 2000). 

O Brien, P. 1972. The sweet potato its origin and dispersal. American Anthropologist J A 342-365. 

Sweet potatoes are well known. The sweet potato (Ipomoea batatas) is of particular interest archaeologically because of questions about its antiquity and its spread across the Pacific. The sweet potato is an important crop in eastern Polynesia (Hawaii, Easter Island, and New Zealand) and the highlands of New Guinea. Yet the original home of the sweet potato is in South America. 

O Brien, P. 1972. The sweet potato its origin and dispersal. American Anthropologist 74 342-365. Oades, J.M. 1993. The role of biology in the formation, stabilization and degradation of soil... 

ORIGIN AND HISTORY. The sweet potato is native to the American tropics. It was once an important component of the Aztec diet. Remains of sweet potatoes estimated to be between 10,000 to 20,000 years old were found in a cave in Peru. However, it is not certain whether the... 

The second argument, on the inactivity of enzymically prepared o-quinone, originates, according to Mallette (1950), from the work of Pugh (1929) and of Bordner and Nelson (1939) with phenolase, and, according to Mason (1956a), from the work of Eiger and Dawson (1949) with sweet potato phenolase and of Bertrand (1949) with laccase. 

---