Table 1. Enrichment of acrosomal membranes in cavitation-released fractions from capacitated sperm.

Enzyme		Specific activity			Purificationa
		whole sperm lysate	1000 g fraction	UCF (285000 g fraction)
Plasma membrane marker b
alkaline phosphatase	capacitated	7.5±0.6	8.8±0.7	79.2±7.3	10.6
	control	6.7±0.5	9.0±3.1	78.3±10.1	11.7
Acrosomal marker
Acrosinc	capacitated	337.8±66.6	251.9±11.8	45.5±2.9e	0.1
	control	323.7±38.6	289.9±34.1	14.1±1.8f	0.04
Outer acrosomal membrane marker
PNA-bindingd	capacitated	509.2±64.9	279.0±13.5	126.6±14.1g	0.3
	control	504.4±58.3	228.4±30.1	72.6±16.9h	0.1

Alkaline phosphatase as a specific plasma membrane indicator for the purity of membrane isolates and acrosin as a marker for the level of acrosome contamination. Peanut Agglutinin (PNA) was used as marker lectin for the outer acrosome membrane material in the 285000 g fraction of the membrane isolates.

^aratio of the specific marker activities between UCF and whole sperm lysate.

^bnmol • mg protein⁻¹ • min⁻¹.

^cµIU: quantity of acrosin • µg protein⁻¹ hydrolyzes 1 µmol BAPNA• min⁻¹ at 22°C.

^dNormalized OD₄₅₀ • µg protein⁻¹ • 10⁹ cell^-1.

• 1000 g fraction contains sperm head

• UCF: Ultra-centrifuge fraction recovered from 285000 g pellet contain membrane vesicles.

• e-f, g-h: significant different for 2-tailed tests between IVF incubations (actual p values for tests between e-f and g-h are both <0.01).

• n≥5, ±s.d.