Enzymatic Action of Basic Arginine Amidases in Human Seminal Plasma

Abstract

Three basic arginine amidases with different affinities to lima bean trypsin inhibitor (LBTI) and aprotinin affinity columns were separated in the middle molecular weight (MMW) preparation obtained from Cellulofine GCL-2000 gel filtration of CM-cellulose adsorbed human seminal plasma and were tentatively called basic human seminal plasma arginine amidase-L (BHSAA-L, with affinity to LBTI), -A (BHSAA-A, with affinity to aprotinin), and -TH (BHSAA-TH, without affinity to either). Some enzymatic properties were measured, including AT; values of LBTI and human seminal plasma proteinase inhibitor (HSP-PI) toward present enzymes. The K_i values of LBTI toward BHSAA-L and -TH were lower than those of HSP-PI and no K_i values for LBTI toward BHSAA-L were observed. The K_m values of BHSAA-L and -A to some tripeptidyl-p-nitroanilide substrates seemed relatively lower than that of BHSAA-TH.

Key Words:

• Human seminal plasma
• Basic arginine amidases
• Affinity adsorption
• Lima bean trypsin inhibitor (LBTI)
• Human seminal plasma proteinase inhibitor
• K_m and K_t measurement.