Biosynthesis of intestinal mucins. 3. Formation of ‘active sulphate’ by cell-free extracts of sheep colonic mucosa

Kent, P. W.; Pasternak, C. A.

doi:10.1042/bj0690453

Cited by 32 publications

(6 citation statements)

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“…This structure has recently been confirmed by chemical synthesis by Bad diley et al (23). The enzyme system that synthesizes PAPS has been found in a variety of plant, animal, and microbial sources, including liver and Neurospora sitophila (20), yeast (24), chick embryo (25), colonic mucosa (26), mast cell tumor (27), Fusarium solani (28), marine algae (29), and the marine snail Busycon (29). The isolation method for substrate amounts of PAPS has been improved recently by Brunngraber (30).…”

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confidence: 64%

Metabolism of Sulfur Compounds (Sulfate Metabolism)

Gregory¹,

Robbins²

1960

Annu. Rev. Biochem.

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SO much work has been published on sulfur compounds in the fourteen years since the last review in this series [Lugg (1)] that we have not attempted to cover the whole field. This paper is regretfully restricted to the metabo lism of sulfate, and many other areas must be slighted in which valuable developments have appeared. However, a few outstanding reviews and general works dealing with particular sulfur compounds should be mentioned: methionine (2), glutathione (3), lipoic acid (4), biotin and other compounds (5), protein sulfhydryl groups (6, 7), and a collection of papers in memory of C. Fromageot, including his complete bibliography (8). General reviews on sulfur metabolism have been published by Bersin (9), Young & Maw (10), and Dziewiatkowski (11).Although many good whole animal studies have appeared on the in corporation and distribution of sulfate [Dziewiatkowski (12)] and on the conjugation of phenolic compounds with sulfate, we shall report mainly en zymological work. Recent knowledge of enzyme reactions involving sulfate has been reviewed by Lipmann (13). The activation of sulfate to form a "high -energy" intermediate is the first step in its assimilation. Two paths are then open: the sulfate may be reduced, or it may be transferred. in which case the reaction is catalyzed by sulfokinases and various esters are formed. And finally, there are hydrolytic enzymes, the sulfatases, which split almost all sulfate esters. SULFATE ACTIVATIONDeMeio and his co-workers were the first to study phenyl sulfate forma tion in a ho mogenate (14). They showed that in a liver homogenate oxygen and mitochondria were necessary for phenyl sulfate synthesis and that ATP would replace these requirements (15). These workers were also among the first to show that the sulfate activating and -transferring systems could be separated (16). Bernstein & McGilvery (17) studied the conjugation of m aminophcnol in liver homogenatcs. By studying the kinetics of this system, they deduced that an intermediate activated sulfate was formed and that at least two enzymes were involved (18). They also showed that a com pound accumulated that would rapidly transfer sulfate when ATP, sulfate, 1 The survey of the literature pertaining to this review was concluded in September 1959.2 The following abbreviations are used in this review: AMP for adenosine mono phosphate; APS for adenosine-5'-phosphosulfate; p-NP and p-NPS for p-nitrophenol and its sulfate, respectively; PAP for 3'-phosphoadenosine-5 '-phosphate; PAPS for 3'-phosphoadenosine-5'-phosphosuJfate; PP for pyrophosphate; TPN+ and TPNH for oxidized and reduced tripho5phopyridine nucle otide, respectively. 347Annu. Rev. Biochem. 1960.29:347-364. Downloaded from www.annualreviews.org Access provided by Western Michigan University on 02/02/15. For personal use only.Quick links to online content Further ANNUAL REVIEWS

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confidence: 64%

Metabolism of Sulfur Compounds (Sulfate Metabolism)

Gregory¹,

Robbins²

1960

Annu. Rev. Biochem.

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“…These (3-phosphoadenosine 5'-phosphosulphate), of which about 20% is available for mucus sulphation and the remainder available for other sulphation processes such as phenolic sulphation.25 26 Sulphotransferases for phenol have been found in the human colon and show I maximal activity in the distal colon.27…”

Section: Discussionmentioning

confidence: 99%

Impaired sulphation of phenol by the colonic mucosa in quiescent and active ulcerative colitis.

Ramakrishna

Pannall

et al. 1991

Gut

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Substantial amounts of phenols are produced in the human colon by bacterial fermentation of protein. In the colonic mucosa of animals, phenols are inactivated predominantly by conjugation with sulphate. The purpose of this study was to confirm sulphation of phenols by isolated colonocytes from man and to evaluate mucosal sulphation in inflammatory bowel disease using the phenol, paracetamol, in rectal dialysis bags. The incubation of paracetamol with colonocytes isolated from resected colon specimens (n=7) yielded a mean (SE) value of 7 0 (0.9) ,tmol/g dry weight of paracetamol sulphate after 60 minutes but virtually undetectable values of paracetamol glucuronide. Paracetamol sulphate was detected in rectal dialysates from all control subjects, with a mean (SE) value of 4-2 (0.8) nmol/hour. Sulphation was significantly impaired (p<0-01) in 19 patients with active ulcerative colitis (0.6 (0 2) nmol/hour) and in 17 patients with ulcerative colitis in remission (1-1 (0-4) nmol/hour). Sulphation in eight patients with Crohn's colitis (4.3 (2.1) nmol/hour) was similar to that in control subjects. Impairment of the capacity of the mucosa to sulphate phenols in quiescent and active ulcerative colitis may pose a metabolic burden on colonic epithelial cells, which are continuously exposed to endogenous phenols from the colonic lumen. The fermentation of protein by bacteria from the human colon generates considerable amounts of phenols and phenylated short chain fatty acids such as phenyl propionate and hydroxyphenyl acetate. ' Some of these volatile phenols may have adverse effects on colonocytes and harmful effects elsewhere in the body.23 In the intact human colon, the concentration of phenols increases progressively from the caecum to the left colon, with maximal concentrations (2 0-3 0 mmol/kg) in the rectosigmoid region.45 Studies in vitro suggest that higher concentrations could be reached under optimal fermentation conditions.6 Although the functional effect of these endogenous phenols remains unclear, the use of an exogenous phenol (paracetamol) has been associated with the onset of exacerbations of ulcerative colitis.7In experimental animals, the inactivation of phenols by the colonic mucosa is mainly achieved by conjugation with sulphate.89 This also seems likely in humans,'0 although studies using colonocytes from resected colon specimens have not been undertaken. The purpose of this study was to examine the sulphation of paracetamol by human colonocytes and to evaluate the sulphation of phenols in inflammatory bowel disease using paracetamol in rectal dialysis bags. Patients and methods STUDIES WITH HUMAN COLONOCYTESColonocytes were isolated from the unaffected mucosa (at least 10 cm from the tumour) of seven colon specimens resected for colonic cancer. Five specimens were from the descending colon and two from the ascending colon. Colonocytes were prepared by mechanical dissociation after incubation in a divalent calcium free solution containing ethylenediaminetetra acetic acid (EDTA

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“…In slices of guinea-pig kidney, SO,2ion (as 0.025M-MgSO4, replacing MgCl2 in the Ringer medium) decreased the amount of o-aminophenyl glucuronide formed by 28 % and in strips of guineapig gastric mucosa by 20 %. As in liver (Storey, 1950), this suggests competition from formation of o-aminophenyl sulphate, which is likely here (Kent & Pasternak, 1958). Carbohydratea. Glucose increased the formation of o-aminophenyl glucuronide in guinea-pig-kidney slices up to 34 % and in gastric-mucosa strips up to 61 % (Table 1).…”

Section: Location Of Uridine Diphosphate-tran8glucuronyla8ementioning

confidence: 65%