Sarcosine metabolism in Haemonchus contortus and Teladorsagia circumcincta

Sarcosine (N-methylglycine) is an intermediate in glycine degradation and can also be synthesised from glycine in mammals. Sarcosine metabolism in Haemonchus contortus and Teladorsagia circumcincta differed from that of mammals in that creatinase activity was present and sarcosine was demethylated only by sarcosine oxidase (SOX) and not by sarcosine dehydrogenase (SDH). The mean SOX activity was 30 nmol min−1 mg−1 protein in homogenates of L3 and adult worms of both parasites and the apparent Km for sarcosine was 1.1 mM. Addition of 2 mM Cd2+ inhibited activity by 30%. There was no SDH activity with either NAD+ or NADP+ as co-factor. Mean creatinase activity in L3 T. circumcincta and adult worms of both species was 31 ± 6 nmol min−1 mg−1 protein, but was undetectable in L3 H. contortus. Activity was inhibited by up to 70% by Cu2+, Fe2+, Fe3+ and Zn2+. Possessing creatinase would allow host creatine to be incorporated into amino acids by the parasites.

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► Creatinase activity in adult H. contortus and T. circumcincta.
► Creatinase activity in L3 T. circumcincta but not H. contortus.
► Creatinase biochemical properties similar to that in bacteria.
► Sarcosine is metabolised by sarcosine oxidase and not by sarcosine dehydrogenase.