ISSN:
0148-7280
Keywords:
human sperm
;
membrane
;
receptors
;
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
Notes:
Binding of N-formyl-methionyl-L-leucyl-[3H]phenylalanine (fML[3H]Ph) to human ejaculated spermatozoa and to its isolated plasma membrane was studied. Our data confirm the presence of specific receptors for f-MLPh in the human spermatozoa and suggest that whole spermatozoa receptors exist in two affinity states, one high-affinity, low-capacity specific receptor (Kd = 12.3 ± 0.5 nM, n = 22,285 ± 65,008 binding sites per sperm cell) and a second one (Kd = 700 ± 47 nM) that is not saturable, indicating a low-affinity, high-capacity nonspecific site. In contrast, sperm membrane showed only one class of binding site (Kd = 6.4 ± 0.12 nM), which was statistically different from that of the high-affinity binding site of intact spermatozoa. To explain this difference we discuss the possibility that first, the two binding affinities represent two interconvertible states of a single receptor population, which, depending on the metabolic activity of spermatozoa, may change its physicochemical properties; or second, they reflect two different processes, binding and/or transport into the spermatozoa.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrd.1120200213
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