Degradation of tissue collagen by hot trichloroacetic acid extraction

✍ Scribed by Ronald O. Langner; Robert A. Newman

• Publisher: Elsevier Science
• Year: 1972
• Tongue: English
• Weight: 363 KB
• Volume: 48
• Category: Article
• ISSN: 0003-2697
• DOI: 10.1016/0003-2697(72)90171-6

✦ Synopsis

Collagen in tissue or tissue ext'racts is usually determined by assaying hydroxyproline, an amino acid unique to collagen. Fitch et nl., in 1955 (l), described a method for measuring the amount of hydroxyproline in acid hydrolyzates of hot trichloroacetic acid (TCA) ext.racts of tissues. They found that hot TCA essentially solubilized all tissue collagen. Peterkofsky and Udenfriend

(2) modified this procedure so as to include precipitation and washing of tissue homogenates with cold TCA, followed by hot TCA extraction and dialysis of the hot TCA soluble material. ID their study they stated that approximately 85% of the hydroxyproline in the material precipitated by cold TCA was extracted with hot TCA in a nondialyzable form. This method of hot TCA extraction followed by dialysis has been used by many investigators studying the biochemical nature of collagen (3-S).

The work presented in this paper describes a possible error which can result from dialysis of hot TCA extracted collagen. ID our studies of rabbit aortic collagen, dialysis of the TCA solubilized collagen consistently resulted in loss of over 507% of the extracted collagen when compared t'o hydroxyprolinc levels of hydrolyzates of tissue homogenates.