-transparent.png){kind=logo}
The quinonoid dihydropterin reductase (DHPR) activity and tetrahydropterin content were determined in human ciliary body--iris, retina, normal lens and senile cataracts. The DHPR activity was higher in the retina [120.56 +/- 12.46 nmol NADH oxidized min-1 (mg soluble protein)-1] than in the ciliary body--iris [46.10 +/- 7.46 nmol NADH oxidized min-1 (mg soluble protein)-1] and lens [2.79 +/- 0.15 nmol NADH oxidized min-1 (mg soluble protein)-1]. In the distribution of DHPR activity in the lens, the capsule-epithelium showed 1.5 and 10 times more activity than the cortex and nucleus, respectively. The apparent Km values for each of the substrates of DHPR activity in lens were obtained by Lineweaver--Burke plots. The plots. The tetrahydropterin content was found to be higher in the retina [826 +/- 76 pmol (g protein)-1] than in the ciliary body--iris [584 +/- 48 pmol (g protein)-1] and lens [82 +/- 16 pmol (g protein)-1]. The DHPR activity and tetrahydropterin content were decreased significantly in senile cataracts as compared with the values of age-matched clear lenses. The importance of the DHPR activity in the maintenance of tetrahydropterin in its reduced form in ocular tissues is discussed.
G N Rao, and
E Cotlier
November 1971,
Annals of the New York Academy of Sciences,
G N Rao, and
E Cotlier
September 1973,
Canadian journal of biochemistry,
G N Rao, and
E Cotlier
November 1977,
Canadian journal of biochemistry,
G N Rao, and
E Cotlier
January 1978,
Biochemical pharmacology,
G N Rao, and
E Cotlier
January 1978,
Biochemical pharmacology,
G N Rao, and
E Cotlier
April 1983,
Biochemistry,
G N Rao, and
E Cotlier
August 1980,
Experimental eye research,
G N Rao, and
E Cotlier
January 1995,
Annals of clinical and laboratory science,
G N Rao, and
E Cotlier
July 1980,
The Journal of biological chemistry,
G N Rao, and
E Cotlier
February 1982,
Experimental eye research,
