
%0 Journal Article
%A Giles, KH 
%A Macmillan, KL 
%T Pyridine Nucleosidase in Bull Semen ll. Biochemical Properties
%J Australian Journal of Biological Sciences
%D 1975/08/01
%V 28
%N 3
%P 273-278
%K 
%R https://doi.org/10.1071/BI9750273
%U https://www.publish.csiro.au/paper/BI9750273 
%X It is most likely a single enzyme (NAD+ nucleosidase) present in semen from most bulls which hydrolyses the ribosyl pyridinium bond in both NAD and NADP. This conclusion is based on the following results: (i) each of 12 semen samples containing nucleosidase activity hydrolysed NAD at the same rate as NADP (r = 0·99); (ii) other untreated semen samples from different bulls which did not hydrolyse NAD were also inactive against NADP; (iii) enzyme denaturation produced by preliminary heating of semen filtrates for 15 min at varied temperatures or by heating at 55°C for varied time intervals caused similar reductions in the rates of NAD and NADP hydrolysis; and (iv) nicotinamide inhibited enzyme activity to the same degree using either NAD or NADP as the substrate. 
