In the presence of N(alpha),N(epsilon)-diacetyl-L-Lys-D-Ala-D-Ala as donor, and either D-[(14)C]alanine, [(14)C]-glycine, or meso-[(3)H]diaminopimelic acid as acceptor, the DD carboxypeptidases from Streptomyces R61 and R39 catalyze a transpeptidation reaction with the release of terminal D-alanine from the donor and the formation of either N(alpha),N(epsilon)-diacetyl-L-Lys-D-Ala-D-[(14)C]Ala,...

In this study a natural culture medium that mimics the synthetic yeast peptone glucose medium used for yeast fermentations was designed to screen and select yeasts capable of producing high levels of diacetyl and acetaldehyde. The presence of whey powder and sodium citrate in the medium along with manganese and magnesium sulfate enhanced both biomass and aroma development. A total of 52 yeasts ...

Apomorphine (APO) is an anti-parkinsonian drug currently in use, which provides relief of Parkinson's symptoms. However, the utility of APO is greatly hampered by its poor bioavailability and rapid metabolism. In the present study, O,O'-diacetyl-apomorphine, a prodrug of apomorphine, was synthesized and its biological activity was examined. The prodrug induced fibroblast growth factor-2 product...

The title co-crystal, C(9)H(9)NO(2)·C(6)H(6)O(2), is composed of one 2,6-diacetyl-pyridine mol-ecule and one resorcinol mol-ecule as the asymmetric unit. In the 2,6-diacetyl-pyridine mol-ecule, the two carbonyl groups are anti-periplanar to the pyridine N atom. In the crystal, the 2,6-diacetyl-pyridine and resorcinol mol-ecules are connected by two O-H⋯O hydrogen bonds, forming planar chains of...

Diacetyl (2,3-butanedione) is a natural ingredient in foodstuffs which is not generally regarded health risk to consumers. Nevertheless, when manufactured for use as a synthetic flavouring/additive in processed foods (e.g. microwave popcorn), it poses a human health threat at the workplace. Its pneumotoxic action consists of inflammation, obstruction and restriction in the distal respiratory tr...

A plasmid-borne diacetyl (acetoin) reductase (butA) from Leuconostoc pseudomesenteroides CHCC2114 was sequenced and cloned. Nucleotide sequence analysis revealed an open reading frame encoding a protein of 257 amino acids which had high identity at the amino acid level to diacetyl (acetoin) reductases reported previously. Downstream of the butA gene of L. pseudomesenteroides, but coding in the ...

Two 2,3-butanediol dehydrogenases (enzymes 1 and 2; molecular weight of each, 170,000) have been partially purified from Lactococcus lactis subsp. lactis (Streptococcus diacetylactis) D10 and shown to have reductase activity with either diacetyl or acetoin as the substrate. However, the reductase activity with 10 mM diacetyl was far greater for both enzymes (7.0- and 4.7-fold for enzymes 1 and ...

Artificial butter flavoring and two important constituents, diacetyl and acetoin, were nominated by the United Food and Commercial Workers International Union for long-term testing via inhalation for respiratory and other toxicity and for cancer-causing properties. There is growing concern that workers in the microwave popcorn manufacturing industry may be at risk of developing the lung disease...

Diacetyl has been associated with the "buttermilk off-flavor" sometimes found in orange juice and in frozen concentrated orange juice. Bacteria of the Lactobacillus and Leuconostoc genera have been identified as causative agents of this type of spoilage (Hays, 1951; Hays and Riester, 1952; Murdock et al., 1952, 1953; and Hill et al., 1954). Growth rates of these spoilage organisms have been inv...

Artificial butter flavoring and two important constituents, diacetyl and acetoin, were nominated by the United Food and Commercial Workers International Union for long-term testing via inhalation for respiratory and other toxicity and for cancer-causing properties. There is growing concern that workers in the microwave popcorn manufacturing industry may be at risk of developing the lung disease...