Notes from the biochemical research foundation

✍ Scribed by Ellice McDonald

• Publisher: Elsevier Science
• Year: 1952
• Tongue: English
• Weight: 36 KB
• Volume: 253
• Category: Article
• ISSN: 0016-0032
• DOI: 10.1016/0016-0032(52)90705-9

✦ Synopsis

of Choline Oxidase Activity in Rat Liver during 3'-Methyl-4-Dimethylaminoazobenzene Carcinogenesis.--G. E. WOODWARD (Cancer Research, 11,918 (1951). The rate of oxidation of choline at pH 7.8 in liver homogenates from rats on a carcinogenic diet containing 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB) has been found to be about 25 per cent of that in homogenates from normal or control rats. The retardation in activity was almost as great after 14 days of feeding 3'-Me-DAB as after more prolonged feeding. The activity in the liver tumor homogenates was less than 5 per cent of that in normal or control liver homogenates and less than 20 per cent of that in 3'-Me-DAB liver homogenates.

3'-Me-DAB liver or liver tumor homogenates, at pH 7.8 or 7.2, produced predominantly more betaine aldehyde than betaine as the end-products of the oxidation of choline, while normal or control liver homogenates produced only betaine. At pH 6.7, 3'-Me-DAB liver and liver tumor homogenates produced little or no oxidation of choline, even to the aldehyde, while normal and control liver homogenates produced both betaine aldehyde and betaine. 62x